From Newsgroup: talk.origins

https://www.science.org/content/article/ant-queen-lays-eggs-hatch-two-species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian
harvester ant (Messor ibericus) takes the weirdness to the next level.
Queens mate with males of another species and then clone them,
researchers report today in Nature, which means this ant is the only
known organism that propagates two species by itself. Evolutionary
biologist Jonathan Romiguier of the University of Montpellier, who led
the team, calls M. ibericus rCLin a sense, the most complex, colonial life form we know of so far.rCY

The researchers think the M. ibericus queens are cloning the M. structor males. The queens allow the M. structor sperm to enter their eggs, but
at some point they remove their own genes from the eggrCOs nucleus to
prevent fertilization, thereby ensuring the egg develops into a male and
not a sterile female worker. By keeping these cloned males on hand, M. ibericus ant colonies can live in places that lack M. structor.
--
Mark Isaak
"Wisdom begins when you discover the difference between 'That
doesn't make sense' and 'I don't understand.'" - Mary Doria Russell

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-hatch-two-species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian
harvester ant (Messor ibericus) takes the weirdness to the next level. Queens mate with males of another species and then clone them,
researchers report today in Nature, which means this ant is the only
known organism that propagates two species by itself. Evolutionary
biologist Jonathan Romiguier of the University of Montpellier, who led
the team, calls M. ibericus rCLin a sense, the most complex, colonial life form we know of so far.rCY

The researchers think the M. ibericus queens are cloning the M. structor males. The queens allow the M. structor sperm to enter their eggs, but
at some point they remove their own genes from the eggrCOs nucleus to prevent fertilization, thereby ensuring the egg develops into a male and
not a sterile female worker. By keeping these cloned males on hand, M. ibericus ant colonies can live in places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they
inviable? What happens to unfertilized eggs with M. ibericus genomes? Or
if there aren't any, why not?

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-hatch-two-
species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian
harvester ant (Messor ibericus) takes the weirdness to the next level.
Queens mate with males of another species and then clone them,
researchers report today in Nature, which means this ant is the only
known organism that propagates two species by itself. Evolutionary
biologist Jonathan Romiguier of the University of Montpellier, who led
the team, calls M. ibericus rCLin a sense, the most complex, colonial
life form we know of so far.rCY

The researchers think the M. ibericus queens are cloning the M.
structor males. The queens allow the M. structor sperm to enter their
eggs, but at some point they remove their own genes from the eggrCOs
nucleus to prevent fertilization, thereby ensuring the egg develops
into a male and not a sterile female worker. By keeping these cloned
males on hand, M. ibericus ant colonies can live in places that lack
M. structor.

Unanswered question: why won't M. ibericus males work? Are they
inviable? What happens to unfertilized eggs with M. ibericus genomes? Or
if there aren't any, why not?

It sounds like no M. ibericus males are produced. My guess is that
since the ants remain highly polymorphic (not inbred) they can go
through genetic recombination, but there is a non disjunction at Meiosis
I so you get one empty egg cell and one tetraploid egg cell. This would
make half the possible eggs empty (0N). At meiosis two you separate the
two chromatids and end up with diploid eggs that has recombined queen chromosomes, so you do not lose the genetic heterozygousity found in the queen. Eggs she allows to be fertilized produce triploid (probably
inviable) zygotes and haploid male M. structor males. The triploids
would die and account for not all male eggs hatching. The unfertilized
eggs produce normal diploid female M. ibericus ants or empty eggs. I do
not know how many empty eggs are produced because they may
preferentially become polar bodies. You have 3 polar bodies and one
large egg cell as products of female meiosis. For males all the cells
turn into sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid the
ants would become highly inbred and would soon be pure M. structor DNA.

It could be a case of Dawkin's selfish DNA. The DNA of the queen
devised a means of perpetuating its genetics in a way that prevented inbreeding depression, while being able to generate new segregating
genetic diversity among the daughter queens if the ants still have
genetic recombination before Meiosis I.

Ron Okimoto

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 9/5/25 7:09 PM, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-hatch-two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian
harvester ant (Messor ibericus) takes the weirdness to the next
level. Queens mate with males of another species and then clone them,
researchers report today in Nature, which means this ant is the only
known organism that propagates two species by itself. Evolutionary
biologist Jonathan Romiguier of the University of Montpellier, who
led the team, calls M. ibericus rCLin a sense, the most complex,
colonial life form we know of so far.rCY

The researchers think the M. ibericus queens are cloning the M.
structor males. The queens allow the M. structor sperm to enter their
eggs, but at some point they remove their own genes from the eggrCOs
nucleus to prevent fertilization, thereby ensuring the egg develops
into a male and not a sterile female worker. By keeping these cloned
males on hand, M. ibericus ant colonies can live in places that lack
M. structor.

Unanswered question: why won't M. ibericus males work? Are they
inviable? What happens to unfertilized eggs with M. ibericus genomes?
Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is that
since the ants remain highly polymorphic (not inbred) they can go
through genetic recombination, but there is a non disjunction at Meiosis
I so you get one empty egg cell and one tetraploid egg cell.-a This would make half the possible eggs empty (0N).-a At meiosis two you separate the two chromatids and end up with diploid eggs that has recombined queen chromosomes, so you do not lose the genetic heterozygousity found in the queen.-a Eggs she allows to be fertilized produce triploid (probably inviable) zygotes and haploid male M. structor males.-a The triploids
would die and account for not all male eggs hatching.-a The unfertilized eggs produce normal diploid female M. ibericus ants or empty eggs.-a I do not know how many empty eggs are produced because they may
preferentially become polar bodies.-a You have 3 polar bodies and one
large egg cell as products of female meiosis.-a For males all the cells
turn into sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid the
ants would become highly inbred and would soon be pure M. structor DNA.

That's certainly a possible mechanism. But in that case what's the point
of having males at all? What you describe is just parthenogenesis. Now
it's true that some parthenogenetic species (Sceloporus lizards, for
example) still mate with males of some other species, necessary for reproduction for some reason even though the male contributes nothing to
the next generation. Perhaps this is such a situation, though I don't
know why mating is required.

I had assumed that females result from fertilized eggs, each with a
full, haploid M. structor genome and a haploid M. ibericus genome. Of
course the problem with that is how you would get genetic divergence
between the species, given recombination during meiosis.

It could be a case of Dawkin's selfish DNA.-a The DNA of the queen
devised a means of perpetuating its genetics in a way that prevented inbreeding depression, while being able to generate new segregating
genetic diversity among the daughter queens if the ants still have
genetic recombination before Meiosis I.

How can you get or retain much diversity? Wouldn't that result in
complete homozygosity after only a few generations? The male is
contributing nothing.

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 06/09/2025 03:09, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-hatch-
two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian
harvester ant (Messor ibericus) takes the weirdness to the next
level. Queens mate with males of another species and then clone them,
researchers report today in Nature, which means this ant is the only
known organism that propagates two species by itself. Evolutionary
biologist Jonathan Romiguier of the University of Montpellier, who
led the team, calls M. ibericus rCLin a sense, the most complex,
colonial life form we know of so far.rCY

The researchers think the M. ibericus queens are cloning the M.
structor males. The queens allow the M. structor sperm to enter their
eggs, but at some point they remove their own genes from the eggrCOs
nucleus to prevent fertilization, thereby ensuring the egg develops
into a male and not a sterile female worker. By keeping these cloned
males on hand, M. ibericus ant colonies can live in places that lack
M. structor.

Unanswered question: why won't M. ibericus males work? Are they
inviable? What happens to unfertilized eggs with M. ibericus genomes?
Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is that
since the ants remain highly polymorphic (not inbred) they can go
through genetic recombination, but there is a non disjunction at Meiosis
I so you get one empty egg cell and one tetraploid egg cell.-a This would make half the possible eggs empty (0N).-a At meiosis two you separate the two chromatids and end up with diploid eggs that has recombined queen chromosomes, so you do not lose the genetic heterozygousity found in the queen.-a Eggs she allows to be fertilized produce triploid (probably inviable) zygotes and haploid male M. structor males.-a The triploids
would die and account for not all male eggs hatching.-a The unfertilized eggs produce normal diploid female M. ibericus ants or empty eggs.-a I do not know how many empty eggs are produced because they may
preferentially become polar bodies.-a You have 3 polar bodies and one
large egg cell as products of female meiosis.-a For males all the cells
turn into sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid the
ants would become highly inbred and would soon be pure M. structor DNA.

It could be a case of Dawkin's selfish DNA.-a The DNA of the queen
devised a means of perpetuating its genetics in a way that prevented inbreeding depression, while being able to generate new segregating
genetic diversity among the daughter queens if the ants still have
genetic recombination before Meiosis I.

I don't find obvious which species is doing the exploiting. It reminds
me of androgenesis in Cupressus dupreziana. That species produces
diploid pollen, which after fertilisation somehow disposes of the
maternal genome, thereby cloning the male parent. (With the possible
exception of plastid and mitochondrial genomes, but the default is
paternal inheritance of plastids in Pinaceae and of both in other conifers.)

It also reminds me of Rana esculentus.
--
alias Ernest Major

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 9/5/2025 10:53 PM, John Harshman wrote:

On 9/5/25 7:09 PM, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-hatch-
two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian
harvester ant (Messor ibericus) takes the weirdness to the next
level. Queens mate with males of another species and then clone
them, researchers report today in Nature, which means this ant is
the only known organism that propagates two species by itself.
Evolutionary biologist Jonathan Romiguier of the University of
Montpellier, who led the team, calls M. ibericus rCLin a sense, the
most complex, colonial life form we know of so far.rCY

The researchers think the M. ibericus queens are cloning the M.
structor males. The queens allow the M. structor sperm to enter
their eggs, but at some point they remove their own genes from the
eggrCOs nucleus to prevent fertilization, thereby ensuring the egg
develops into a male and not a sterile female worker. By keeping
these cloned males on hand, M. ibericus ant colonies can live in
places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they
inviable? What happens to unfertilized eggs with M. ibericus genomes?
Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is that
since the ants remain highly polymorphic (not inbred) they can go
through genetic recombination, but there is a non disjunction at
Meiosis I so you get one empty egg cell and one tetraploid egg cell.
This would make half the possible eggs empty (0N).-a At meiosis two you
separate the two chromatids and end up with diploid eggs that has
recombined queen chromosomes, so you do not lose the genetic
heterozygousity found in the queen.-a Eggs she allows to be fertilized
produce triploid (probably inviable) zygotes and haploid male M.
structor males.-a The triploids would die and account for not all male
eggs hatching.-a The unfertilized eggs produce normal diploid female M.
ibericus ants or empty eggs.-a I do not know how many empty eggs are
produced because they may preferentially become polar bodies.-a You
have 3 polar bodies and one large egg cell as products of female
meiosis.-a For males all the cells turn into sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid the
ants would become highly inbred and would soon be pure M. structor DNA.

That's certainly a possible mechanism. But in that case what's the point
of having males at all? What you describe is just parthenogenesis. Now
it's true that some parthenogenetic species (Sceloporus lizards, for example) still mate with males of some other species, necessary for reproduction for some reason even though the male contributes nothing to
the next generation. Perhaps this is such a situation, though I don't
know why mating is required.

Some animals like some of the triploid parthenogenetic lizards need to
mate in order to stimulate egg production. The lizards do not use the
male sperm, but produce parthenogenetic offspring with the female's
triploid genetics.

The ant male DNA also benefits from this arrangement. Clonal offspring
are produce that keep perpetuating the male's DNA each generation. It
is pretty much a win win for the selfish DNA. The DNA of two divergent species is preserved in one population, and they are preserved as intact genomes.

I had assumed that females result from fertilized eggs, each with a
full, haploid M. structor genome and a haploid M. ibericus genome. Of
course the problem with that is how you would get genetic divergence
between the species, given recombination during meiosis.

You might get recombination if the chromosomes match up, but after
repeated generations using the cloned male genome the species would
eventually become inbred M. structor, so there would be a species switch eventually. The first generation you get 50% M. structor DNA. The next generation you become 75% M. structor DNA. The next generation you get
87.5% M. Structor offspring etc.. So when they claimed that the genomes remained highly polymorphic and M. ibericus I assumed that any hybrids
had to be dead.

It could be a case of Dawkin's selfish DNA.-a The DNA of the queen
devised a means of perpetuating its genetics in a way that prevented
inbreeding depression, while being able to generate new segregating
genetic diversity among the daughter queens if the ants still have
genetic recombination before Meiosis I.

How can you get or retain much diversity? Wouldn't that result in
complete homozygosity after only a few generations? The male is
contributing nothing.

If the nondisjuction event occurs in meiosis I, meiosis II results in chromatid splitting in a full diploid genome. I called this a
tetraploid egg because that is what the composition of the egg cell
would be if you started with a tetraploid and had a normal Meiosis I separation of homologous chromosomes.

Since recombination occurs before Meiosis I you maintain genetic
diversity and do not just produce clones. When the chromatids split at Meiosis II, recombined genetically unique chromosomes can go into each
egg cell.

I used to make my genetic students understand Meiosis. I would tell
them that if they understood meiosis that they would understand
Mendelian genetics.

Ron Okimoto

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 9/6/2025 5:23 AM, Ernest Major wrote:

On 06/09/2025 03:09, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-hatch-
two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian
harvester ant (Messor ibericus) takes the weirdness to the next
level. Queens mate with males of another species and then clone
them, researchers report today in Nature, which means this ant is
the only known organism that propagates two species by itself.
Evolutionary biologist Jonathan Romiguier of the University of
Montpellier, who led the team, calls M. ibericus rCLin a sense, the
most complex, colonial life form we know of so far.rCY

The researchers think the M. ibericus queens are cloning the M.
structor males. The queens allow the M. structor sperm to enter
their eggs, but at some point they remove their own genes from the
eggrCOs nucleus to prevent fertilization, thereby ensuring the egg
develops into a male and not a sterile female worker. By keeping
these cloned males on hand, M. ibericus ant colonies can live in
places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they
inviable? What happens to unfertilized eggs with M. ibericus genomes?
Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is that
since the ants remain highly polymorphic (not inbred) they can go
through genetic recombination, but there is a non disjunction at
Meiosis I so you get one empty egg cell and one tetraploid egg cell.
This would make half the possible eggs empty (0N).-a At meiosis two you
separate the two chromatids and end up with diploid eggs that has
recombined queen chromosomes, so you do not lose the genetic
heterozygousity found in the queen.-a Eggs she allows to be fertilized
produce triploid (probably inviable) zygotes and haploid male M.
structor males.-a The triploids would die and account for not all male
eggs hatching.-a The unfertilized eggs produce normal diploid female M.
ibericus ants or empty eggs.-a I do not know how many empty eggs are
produced because they may preferentially become polar bodies.-a You
have 3 polar bodies and one large egg cell as products of female
meiosis.-a For males all the cells turn into sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid the
ants would become highly inbred and would soon be pure M. structor DNA.

It could be a case of Dawkin's selfish DNA.-a The DNA of the queen
devised a means of perpetuating its genetics in a way that prevented
inbreeding depression, while being able to generate new segregating
genetic diversity among the daughter queens if the ants still have
genetic recombination before Meiosis I.

I don't find obvious which species is doing the exploiting. It reminds
me of androgenesis in Cupressus dupreziana. That species produces
diploid pollen, which after fertilisation somehow disposes of the
maternal genome, thereby cloning the male parent. (With the possible exception of plastid and mitochondrial genomes, but the default is
paternal inheritance of plastids in Pinaceae and of both in other
conifers.)

It also reminds me of Rana esculentus.

As I just commented to Harshman this conforms to selfish DNA for both
species. The M. structor genome is cloned each generation, and the M. ibericus queen's genome is transmitted to the next generation without inbreeding or mixing with someone elses DNA. Both genomes are
maintained intact and not hybrid in a single population. Both genomes
get propagated and preserve their genetic identity. That is all selfish
DNA would want to do.

Ron Okimoto

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 9/6/25 6:40 AM, RonO wrote:

On 9/5/2025 10:53 PM, John Harshman wrote:

On 9/5/25 7:09 PM, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-hatch-
two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian
harvester ant (Messor ibericus) takes the weirdness to the next
level. Queens mate with males of another species and then clone
them, researchers report today in Nature, which means this ant is
the only known organism that propagates two species by itself.
Evolutionary biologist Jonathan Romiguier of the University of
Montpellier, who led the team, calls M. ibericus rCLin a sense, the >>>>> most complex, colonial life form we know of so far.rCY

The researchers think the M. ibericus queens are cloning the M.
structor males. The queens allow the M. structor sperm to enter
their eggs, but at some point they remove their own genes from the
eggrCOs nucleus to prevent fertilization, thereby ensuring the egg
develops into a male and not a sterile female worker. By keeping
these cloned males on hand, M. ibericus ant colonies can live in
places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they
inviable? What happens to unfertilized eggs with M. ibericus
genomes? Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is that
since the ants remain highly polymorphic (not inbred) they can go
through genetic recombination, but there is a non disjunction at
Meiosis I so you get one empty egg cell and one tetraploid egg cell.
This would make half the possible eggs empty (0N).-a At meiosis two
you separate the two chromatids and end up with diploid eggs that has
recombined queen chromosomes, so you do not lose the genetic
heterozygousity found in the queen.-a Eggs she allows to be fertilized
produce triploid (probably inviable) zygotes and haploid male M.
structor males.-a The triploids would die and account for not all male
eggs hatching.-a The unfertilized eggs produce normal diploid female
M. ibericus ants or empty eggs.-a I do not know how many empty eggs
are produced because they may preferentially become polar bodies.
You have 3 polar bodies and one large egg cell as products of female
meiosis.-a For males all the cells turn into sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid the
ants would become highly inbred and would soon be pure M. structor DNA.

That's certainly a possible mechanism. But in that case what's the
point of having males at all? What you describe is just
parthenogenesis. Now it's true that some parthenogenetic species
(Sceloporus lizards, for example) still mate with males of some other
species, necessary for reproduction for some reason even though the
male contributes nothing to the next generation. Perhaps this is such
a situation, though I don't know why mating is required.

Some animals like some of the triploid parthenogenetic lizards need to
mate in order to stimulate egg production.-a The lizards do not use the
male sperm, but produce parthenogenetic offspring with the female's
triploid genetics.

As I said. But what's the point of the male for the ants?

The ant male DNA also benefits from this arrangement.-a Clonal offspring
are produce that keep perpetuating the male's DNA each generation.-a It
is pretty much a win win for the selfish DNA.-a The DNA of two divergent species is preserved in one population, and they are preserved as intact genomes.

Again, what benefit does the female genome derive from this process? Why wouldn't evolution dispense with the male, unless it has some essential function that's hard to get rid of?

I had assumed that females result from fertilized eggs, each with a
full, haploid M. structor genome and a haploid M. ibericus genome. Of
course the problem with that is how you would get genetic divergence
between the species, given recombination during meiosis.

You might get recombination if the chromosomes match up, but after
repeated generations using the cloned male genome the species would eventually become inbred M. structor, so there would be a species switch eventually.-a The first generation you get 50% M. structor DNA.-a The next generation you become 75% M. structor DNA.-a The next generation you get 87.5% M. Structor offspring etc..-a So when they claimed that the genomes remained highly polymorphic and M. ibericus I assumed that any hybrids
had to be dead.

It could be a case of Dawkin's selfish DNA.-a The DNA of the queen
devised a means of perpetuating its genetics in a way that prevented
inbreeding depression, while being able to generate new segregating
genetic diversity among the daughter queens if the ants still have
genetic recombination before Meiosis I.

How can you get or retain much diversity? Wouldn't that result in
complete homozygosity after only a few generations? The male is
contributing nothing.

If the nondisjuction event occurs in meiosis I, meiosis II results in chromatid splitting in a full diploid genome.-a I called this a
tetraploid egg because that is what the composition of the egg cell
would be if you started with a tetraploid and had a normal Meiosis I separation of homologous chromosomes.

Since recombination occurs before Meiosis I you maintain genetic
diversity and do not just produce clones.-a When the chromatids split at Meiosis II, recombined genetically unique chromosomes can go into each
egg cell.

I used to make my genetic students understand Meiosis.-a I would tell
them that if they understood meiosis that they would understand
Mendelian genetics.

Nevertheless, you start with a single diploid individual, and that's
limited genetic diversity. Recombination within a single genome can only introduce a little, and mutation a little. Keeping in mind that the
effective population size (queens only) is likely to be small, how is
any significant diversity maintained?

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 9/6/25 6:51 AM, RonO wrote:

On 9/6/2025 5:23 AM, Ernest Major wrote:

On 06/09/2025 03:09, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-hatch-
two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian
harvester ant (Messor ibericus) takes the weirdness to the next
level. Queens mate with males of another species and then clone
them, researchers report today in Nature, which means this ant is
the only known organism that propagates two species by itself.
Evolutionary biologist Jonathan Romiguier of the University of
Montpellier, who led the team, calls M. ibericus rCLin a sense, the >>>>> most complex, colonial life form we know of so far.rCY

The researchers think the M. ibericus queens are cloning the M.
structor males. The queens allow the M. structor sperm to enter
their eggs, but at some point they remove their own genes from the
eggrCOs nucleus to prevent fertilization, thereby ensuring the egg
develops into a male and not a sterile female worker. By keeping
these cloned males on hand, M. ibericus ant colonies can live in
places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they
inviable? What happens to unfertilized eggs with M. ibericus
genomes? Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is that
since the ants remain highly polymorphic (not inbred) they can go
through genetic recombination, but there is a non disjunction at
Meiosis I so you get one empty egg cell and one tetraploid egg cell.
This would make half the possible eggs empty (0N).-a At meiosis two
you separate the two chromatids and end up with diploid eggs that has
recombined queen chromosomes, so you do not lose the genetic
heterozygousity found in the queen.-a Eggs she allows to be fertilized
produce triploid (probably inviable) zygotes and haploid male M.
structor males.-a The triploids would die and account for not all male
eggs hatching.-a The unfertilized eggs produce normal diploid female
M. ibericus ants or empty eggs.-a I do not know how many empty eggs
are produced because they may preferentially become polar bodies.
You have 3 polar bodies and one large egg cell as products of female
meiosis.-a For males all the cells turn into sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid the
ants would become highly inbred and would soon be pure M. structor DNA.

It could be a case of Dawkin's selfish DNA.-a The DNA of the queen
devised a means of perpetuating its genetics in a way that prevented
inbreeding depression, while being able to generate new segregating
genetic diversity among the daughter queens if the ants still have
genetic recombination before Meiosis I.

I don't find obvious which species is doing the exploiting. It reminds
me of androgenesis in Cupressus dupreziana. That species produces
diploid pollen, which after fertilisation somehow disposes of the
maternal genome, thereby cloning the male parent. (With the possible
exception of plastid and mitochondrial genomes, but the default is
paternal inheritance of plastids in Pinaceae and of both in other
conifers.)

It also reminds me of Rana esculentus.

As I just commented to Harshman this conforms to selfish DNA for both species.-a The M. structor genome is cloned each generation, and the M. ibericus queen's genome is transmitted to the next generation without inbreeding or mixing with someone elses DNA.-a Both genomes are
maintained intact and not hybrid in a single population.-a Both genomes
get propagated and preserve their genetic identity.-a That is all selfish DNA would want to do.

But the whole mechanism for all this is in the female genome. So how
does the male genome manage to assert its advantage when the female
derives no advantage from the association?

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 9/6/2025 9:09 AM, John Harshman wrote:

On 9/6/25 6:40 AM, RonO wrote:

On 9/5/2025 10:53 PM, John Harshman wrote:

On 9/5/25 7:09 PM, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-hatch- >>>>>> two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian
harvester ant (Messor ibericus) takes the weirdness to the next
level. Queens mate with males of another species and then clone
them, researchers report today in Nature, which means this ant is >>>>>> the only known organism that propagates two species by itself.
Evolutionary biologist Jonathan Romiguier of the University of
Montpellier, who led the team, calls M. ibericus rCLin a sense, the >>>>>> most complex, colonial life form we know of so far.rCY

The researchers think the M. ibericus queens are cloning the M.
structor males. The queens allow the M. structor sperm to enter
their eggs, but at some point they remove their own genes from the >>>>>> eggrCOs nucleus to prevent fertilization, thereby ensuring the egg >>>>>> develops into a male and not a sterile female worker. By keeping
these cloned males on hand, M. ibericus ant colonies can live in
places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they
inviable? What happens to unfertilized eggs with M. ibericus
genomes? Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is that
since the ants remain highly polymorphic (not inbred) they can go
through genetic recombination, but there is a non disjunction at
Meiosis I so you get one empty egg cell and one tetraploid egg cell.
This would make half the possible eggs empty (0N).-a At meiosis two
you separate the two chromatids and end up with diploid eggs that
has recombined queen chromosomes, so you do not lose the genetic
heterozygousity found in the queen.-a Eggs she allows to be
fertilized produce triploid (probably inviable) zygotes and haploid
male M. structor males.-a The triploids would die and account for not >>>> all male eggs hatching.-a The unfertilized eggs produce normal
diploid female M. ibericus ants or empty eggs.-a I do not know how
many empty eggs are produced because they may preferentially become
polar bodies. You have 3 polar bodies and one large egg cell as
products of female meiosis.-a For males all the cells turn into sperm >>>> cells.

If the M. structor sperm were fertilizing eggs that were haploid the
ants would become highly inbred and would soon be pure M. structor DNA. >>>

That's certainly a possible mechanism. But in that case what's the
point of having males at all? What you describe is just
parthenogenesis. Now it's true that some parthenogenetic species
(Sceloporus lizards, for example) still mate with males of some other
species, necessary for reproduction for some reason even though the
male contributes nothing to the next generation. Perhaps this is such
a situation, though I don't know why mating is required.

Some animals like some of the triploid parthenogenetic lizards need to
mate in order to stimulate egg production.-a The lizards do not use the
male sperm, but produce parthenogenetic offspring with the female's
triploid genetics.

As I said. But what's the point of the male for the ants?

My guess is that the female ants need to be mated before they further
develop into egg laying machines. This allows this species to maintain
the genome of a single queen to be perpetuated, but the daughters are
not clones. Meiotic recombination would scramble the queens chromosomes
so that she would maintain an amazing amount of genetic variation among
her progeny so that further adaptation could occur. If they just kept
mating sibs together in order to maintain the queens genetics they would probably end up with an inbred mess and die out.

The ant male DNA also benefits from this arrangement.-a Clonal
offspring are produce that keep perpetuating the male's DNA each
generation.-a It is pretty much a win win for the selfish DNA.-a The DNA
of two divergent species is preserved in one population, and they are
preserved as intact genomes.

Again, what benefit does the female genome derive from this process? Why wouldn't evolution dispense with the male, unless it has some essential function that's hard to get rid of?

The selfish DNA proposal would have this situation selected for because
it transfers the individual's DNA without having to mix with other DNA.
Both the male's and the queen's DNA get transferred intact to the next generation, and the queen is able to do this in a way that maintains
high genetic variation among her offspring without having to share the
success with someone else.

I had assumed that females result from fertilized eggs, each with a
full, haploid M. structor genome and a haploid M. ibericus genome. Of
course the problem with that is how you would get genetic divergence
between the species, given recombination during meiosis.

You might get recombination if the chromosomes match up, but after
repeated generations using the cloned male genome the species would
eventually become inbred M. structor, so there would be a species
switch eventually.-a The first generation you get 50% M. structor DNA.
The next generation you become 75% M. structor DNA.-a The next
generation you get 87.5% M. Structor offspring etc..-a So when they
claimed that the genomes remained highly polymorphic and M. ibericus I
assumed that any hybrids had to be dead.

It could be a case of Dawkin's selfish DNA.-a The DNA of the queen
devised a means of perpetuating its genetics in a way that prevented
inbreeding depression, while being able to generate new segregating
genetic diversity among the daughter queens if the ants still have
genetic recombination before Meiosis I.

How can you get or retain much diversity? Wouldn't that result in
complete homozygosity after only a few generations? The male is
contributing nothing.

If the nondisjuction event occurs in meiosis I, meiosis II results in
chromatid splitting in a full diploid genome.-a I called this a
tetraploid egg because that is what the composition of the egg cell
would be if you started with a tetraploid and had a normal Meiosis I
separation of homologous chromosomes.

Since recombination occurs before Meiosis I you maintain genetic
diversity and do not just produce clones.-a When the chromatids split
at Meiosis II, recombined genetically unique chromosomes can go into
each egg cell.

I used to make my genetic students understand Meiosis.-a I would tell
them that if they understood meiosis that they would understand
Mendelian genetics.

Nevertheless, you start with a single diploid individual, and that's
limited genetic diversity. Recombination within a single genome can only introduce a little, and mutation a little. Keeping in mind that the effective population size (queens only) is likely to be small, how is
any significant diversity maintained?

Mutation rate is essentially the same because both copies of the genome
of the 2N species is mutated every generation, and only half is
transferred to the next generation. In this case the 2N is transferred
to the next generation, so it is the same as having another half mutated genome incorporated instead. The queen is highly heterozygous and is segregating a lot of genetic variation, but this variation is not
segregating normally. Instead of transferring half of the variation to
the next generation, she is transferring it all, but there are a near
infinite number variant packages that she can transfer when you consider genetic recombination and new mutation. Every meiosis she generates a
whole new set of chromosomal haplotypes to pass on to her offspring.

What is lost is the ability to gain new genetic variants due to normal
sexual reproduction. In this case the queen posesses a highly
polymorphic genome that has been repeatedly tested and won out to create
an expanding population with the same starting genetics. Each new queen
would have a different combination of genetic variation inherited from
the original queen. Any combination that isn't as successful would be
out competed.

Ron Okimoto

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 9/6/2025 9:37 AM, John Harshman wrote:

On 9/6/25 6:51 AM, RonO wrote:

On 9/6/2025 5:23 AM, Ernest Major wrote:

On 06/09/2025 03:09, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-hatch- >>>>>> two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian
harvester ant (Messor ibericus) takes the weirdness to the next
level. Queens mate with males of another species and then clone
them, researchers report today in Nature, which means this ant is >>>>>> the only known organism that propagates two species by itself.
Evolutionary biologist Jonathan Romiguier of the University of
Montpellier, who led the team, calls M. ibericus rCLin a sense, the >>>>>> most complex, colonial life form we know of so far.rCY

The researchers think the M. ibericus queens are cloning the M.
structor males. The queens allow the M. structor sperm to enter
their eggs, but at some point they remove their own genes from the >>>>>> eggrCOs nucleus to prevent fertilization, thereby ensuring the egg >>>>>> develops into a male and not a sterile female worker. By keeping
these cloned males on hand, M. ibericus ant colonies can live in
places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they
inviable? What happens to unfertilized eggs with M. ibericus
genomes? Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is that
since the ants remain highly polymorphic (not inbred) they can go
through genetic recombination, but there is a non disjunction at
Meiosis I so you get one empty egg cell and one tetraploid egg cell.
This would make half the possible eggs empty (0N).-a At meiosis two
you separate the two chromatids and end up with diploid eggs that
has recombined queen chromosomes, so you do not lose the genetic
heterozygousity found in the queen.-a Eggs she allows to be
fertilized produce triploid (probably inviable) zygotes and haploid
male M. structor males.-a The triploids would die and account for not >>>> all male eggs hatching.-a The unfertilized eggs produce normal
diploid female M. ibericus ants or empty eggs.-a I do not know how
many empty eggs are produced because they may preferentially become
polar bodies. You have 3 polar bodies and one large egg cell as
products of female meiosis.-a For males all the cells turn into sperm >>>> cells.

If the M. structor sperm were fertilizing eggs that were haploid the
ants would become highly inbred and would soon be pure M. structor DNA. >>>>
It could be a case of Dawkin's selfish DNA.-a The DNA of the queen
devised a means of perpetuating its genetics in a way that prevented
inbreeding depression, while being able to generate new segregating
genetic diversity among the daughter queens if the ants still have
genetic recombination before Meiosis I.

I don't find obvious which species is doing the exploiting. It
reminds me of androgenesis in Cupressus dupreziana. That species
produces diploid pollen, which after fertilisation somehow disposes
of the maternal genome, thereby cloning the male parent. (With the
possible exception of plastid and mitochondrial genomes, but the
default is paternal inheritance of plastids in Pinaceae and of both
in other conifers.)

It also reminds me of Rana esculentus.

As I just commented to Harshman this conforms to selfish DNA for both
species.-a The M. structor genome is cloned each generation, and the M.
ibericus queen's genome is transmitted to the next generation without
inbreeding or mixing with someone elses DNA.-a Both genomes are
maintained intact and not hybrid in a single population.-a Both genomes
get propagated and preserve their genetic identity.-a That is all
selfish DNA would want to do.

But the whole mechanism for all this is in the female genome. So how
does the male genome manage to assert its advantage when the female
derives no advantage from the association?

The male's DNA benefits from the sperm being slaves to the queen. It
doesn't have to assert any advantage it just has to successfully
replicate, and the females empty (0N) eggs are used to replicate the
male's DNA.

My guess that initially the hybridization between the two species
selected for queens prone to non disjunction in Meiosis I. These
defective queens would have been the ones to benefit from mating with
another species whose DNA they didn't need. For normal matings the
triploids produced would have difficulty reproducing or there might have
been a lot of dead triploid embryos produced, so the queens prone to non disjunction would have been selected against.

Ron Okimoto

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 9/6/25 10:48 AM, RonO wrote:

On 9/6/2025 9:09 AM, John Harshman wrote:

On 9/6/25 6:40 AM, RonO wrote:

On 9/5/2025 10:53 PM, John Harshman wrote:

On 9/5/25 7:09 PM, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-hatch- two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian >>>>>>> harvester ant (Messor ibericus) takes the weirdness to the next >>>>>>> level. Queens mate with males of another species and then clone >>>>>>> them, researchers report today in Nature, which means this ant is >>>>>>> the only known organism that propagates two species by itself.
Evolutionary biologist Jonathan Romiguier of the University of
Montpellier, who led the team, calls M. ibericus rCLin a sense, the >>>>>>> most complex, colonial life form we know of so far.rCY

The researchers think the M. ibericus queens are cloning the M. >>>>>>> structor males. The queens allow the M. structor sperm to enter >>>>>>> their eggs, but at some point they remove their own genes from
the eggrCOs nucleus to prevent fertilization, thereby ensuring the >>>>>>> egg develops into a male and not a sterile female worker. By
keeping these cloned males on hand, M. ibericus ant colonies can >>>>>>> live in places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they
inviable? What happens to unfertilized eggs with M. ibericus
genomes? Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is that >>>>> since the ants remain highly polymorphic (not inbred) they can go
through genetic recombination, but there is a non disjunction at
Meiosis I so you get one empty egg cell and one tetraploid egg
cell. This would make half the possible eggs empty (0N).-a At
meiosis two you separate the two chromatids and end up with diploid >>>>> eggs that has recombined queen chromosomes, so you do not lose the
genetic heterozygousity found in the queen.-a Eggs she allows to be >>>>> fertilized produce triploid (probably inviable) zygotes and haploid >>>>> male M. structor males.-a The triploids would die and account for
not all male eggs hatching.-a The unfertilized eggs produce normal
diploid female M. ibericus ants or empty eggs.-a I do not know how
many empty eggs are produced because they may preferentially become >>>>> polar bodies. You have 3 polar bodies and one large egg cell as
products of female meiosis.-a For males all the cells turn into
sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid
the ants would become highly inbred and would soon be pure M.
structor DNA.

That's certainly a possible mechanism. But in that case what's the
point of having males at all? What you describe is just
parthenogenesis. Now it's true that some parthenogenetic species
(Sceloporus lizards, for example) still mate with males of some
other species, necessary for reproduction for some reason even
though the male contributes nothing to the next generation. Perhaps
this is such a situation, though I don't know why mating is required.

Some animals like some of the triploid parthenogenetic lizards need
to mate in order to stimulate egg production.-a The lizards do not use
the male sperm, but produce parthenogenetic offspring with the
female's triploid genetics.

As I said. But what's the point of the male for the ants?

My guess is that the female ants need to be mated before they further develop into egg laying machines.-a This allows this species to maintain
the genome of a single queen to be perpetuated, but the daughters are
not clones.-a Meiotic recombination would scramble the queens chromosomes
so that she would maintain an amazing amount of genetic variation among
her progeny so that further adaptation could occur.-a If they just kept mating sibs together in order to maintain the queens genetics they would probably end up with an inbred mess and die out.

One diploid individual is an extreme bottleneck, and couldn't contain
all that much genetic variation. And recombination within a single
diploid genome isn't generating much new variation.

The ant male DNA also benefits from this arrangement.-a Clonal
offspring are produce that keep perpetuating the male's DNA each
generation.-a It is pretty much a win win for the selfish DNA.-a The
DNA of two divergent species is preserved in one population, and they
are preserved as intact genomes.

Again, what benefit does the female genome derive from this process?
Why wouldn't evolution dispense with the male, unless it has some
essential function that's hard to get rid of?

The selfish DNA proposal would have this situation selected for because
it transfers the individual's DNA without having to mix with other DNA.

The queen's DNA shouldn't care what happens to the male's DNA. And the
male's DNA has no power to influence its own reproduction. So we still
have to ask why the queen would bother mating at all.

Both the male's and the queen's DNA get transferred intact to the next generation, and the queen is able to do this in a way that maintains
high genetic variation among her offspring without having to share the success with someone else.

Yet this ability does not depend on preserving the male's genome or upon mating with a male.

I had assumed that females result from fertilized eggs, each with a
full, haploid M. structor genome and a haploid M. ibericus genome.
Of course the problem with that is how you would get genetic
divergence between the species, given recombination during meiosis.

You might get recombination if the chromosomes match up, but after
repeated generations using the cloned male genome the species would
eventually become inbred M. structor, so there would be a species
switch eventually.-a The first generation you get 50% M. structor DNA.
The next generation you become 75% M. structor DNA.-a The next
generation you get 87.5% M. Structor offspring etc..-a So when they
claimed that the genomes remained highly polymorphic and M. ibericus
I assumed that any hybrids had to be dead.

It could be a case of Dawkin's selfish DNA.-a The DNA of the queen
devised a means of perpetuating its genetics in a way that
prevented inbreeding depression, while being able to generate new
segregating genetic diversity among the daughter queens if the ants >>>>> still have genetic recombination before Meiosis I.

How can you get or retain much diversity? Wouldn't that result in
complete homozygosity after only a few generations? The male is
contributing nothing.

If the nondisjuction event occurs in meiosis I, meiosis II results in
chromatid splitting in a full diploid genome.-a I called this a
tetraploid egg because that is what the composition of the egg cell
would be if you started with a tetraploid and had a normal Meiosis I
separation of homologous chromosomes.

Since recombination occurs before Meiosis I you maintain genetic
diversity and do not just produce clones.-a When the chromatids split
at Meiosis II, recombined genetically unique chromosomes can go into
each egg cell.

I used to make my genetic students understand Meiosis.-a I would tell
them that if they understood meiosis that they would understand
Mendelian genetics.

Nevertheless, you start with a single diploid individual, and that's
limited genetic diversity. Recombination within a single genome can
only introduce a little, and mutation a little. Keeping in mind that
the effective population size (queens only) is likely to be small, how
is any significant diversity maintained?

Mutation rate is essentially the same because both copies of the genome
of the 2N species is mutated every generation, and only half is
transferred to the next generation.-a In this case the 2N is transferred
to the next generation, so it is the same as having another half mutated genome incorporated instead.-a The queen is highly heterozygous and is segregating a lot of genetic variation, but this variation is not segregating normally.

Is the queen in fact highly heterozygous? What maintains heterozygosity?
Does recombination, in most cases, even produce selectable variation?
Most of the genome is junk, and the bits that aren't mostly don't care
which chromatid they're on or which nearby variants are on. I can see crossover within an exon possibly producing a new, functionally
different allele, but how often would even that happen?

Instead of transferring half of the variation to
the next generation, she is transferring it all, but there are a near infinite number variant packages that she can transfer when you consider genetic recombination and new mutation.-a Every meiosis she generates a whole new set of chromosomal haplotypes to pass on to her offspring.

Yes, but how many of them have any functional differences. The genome is transferred with all the same bases, just swapped to different
chromatids now and then. Heterozygosity increases only through mutation.

What is lost is the ability to gain new genetic variants due to normal sexual reproduction.-a In this case the queen posesses a highly
polymorphic genome that has been repeatedly tested and won out to create
an expanding population with the same starting genetics.

Again, do you actually know that the genome is highly polymorphic,
whatever that means in an effective population size of one?

Each new queen
would have a different combination of genetic variation inherited from
the original queen.-a Any combination that isn't as successful would be
out competed.

I just can't see recombination of this sort as producing much selectable variation.

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 9/6/25 11:00 AM, RonO wrote:

On 9/6/2025 9:37 AM, John Harshman wrote:

On 9/6/25 6:51 AM, RonO wrote:

On 9/6/2025 5:23 AM, Ernest Major wrote:

On 06/09/2025 03:09, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-hatch- two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian >>>>>>> harvester ant (Messor ibericus) takes the weirdness to the next >>>>>>> level. Queens mate with males of another species and then clone >>>>>>> them, researchers report today in Nature, which means this ant is >>>>>>> the only known organism that propagates two species by itself.
Evolutionary biologist Jonathan Romiguier of the University of
Montpellier, who led the team, calls M. ibericus rCLin a sense, the >>>>>>> most complex, colonial life form we know of so far.rCY

The researchers think the M. ibericus queens are cloning the M. >>>>>>> structor males. The queens allow the M. structor sperm to enter >>>>>>> their eggs, but at some point they remove their own genes from
the eggrCOs nucleus to prevent fertilization, thereby ensuring the >>>>>>> egg develops into a male and not a sterile female worker. By
keeping these cloned males on hand, M. ibericus ant colonies can >>>>>>> live in places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they
inviable? What happens to unfertilized eggs with M. ibericus
genomes? Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is that >>>>> since the ants remain highly polymorphic (not inbred) they can go
through genetic recombination, but there is a non disjunction at
Meiosis I so you get one empty egg cell and one tetraploid egg
cell. This would make half the possible eggs empty (0N).-a At
meiosis two you separate the two chromatids and end up with diploid >>>>> eggs that has recombined queen chromosomes, so you do not lose the
genetic heterozygousity found in the queen.-a Eggs she allows to be >>>>> fertilized produce triploid (probably inviable) zygotes and haploid >>>>> male M. structor males.-a The triploids would die and account for
not all male eggs hatching.-a The unfertilized eggs produce normal
diploid female M. ibericus ants or empty eggs.-a I do not know how
many empty eggs are produced because they may preferentially become >>>>> polar bodies. You have 3 polar bodies and one large egg cell as
products of female meiosis.-a For males all the cells turn into
sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid
the ants would become highly inbred and would soon be pure M.
structor DNA.

It could be a case of Dawkin's selfish DNA.-a The DNA of the queen
devised a means of perpetuating its genetics in a way that
prevented inbreeding depression, while being able to generate new
segregating genetic diversity among the daughter queens if the ants >>>>> still have genetic recombination before Meiosis I.

I don't find obvious which species is doing the exploiting. It
reminds me of androgenesis in Cupressus dupreziana. That species
produces diploid pollen, which after fertilisation somehow disposes
of the maternal genome, thereby cloning the male parent. (With the
possible exception of plastid and mitochondrial genomes, but the
default is paternal inheritance of plastids in Pinaceae and of both
in other conifers.)

It also reminds me of Rana esculentus.

As I just commented to Harshman this conforms to selfish DNA for both
species.-a The M. structor genome is cloned each generation, and the
M. ibericus queen's genome is transmitted to the next generation
without inbreeding or mixing with someone elses DNA.-a Both genomes
are maintained intact and not hybrid in a single population.-a Both
genomes get propagated and preserve their genetic identity.-a That is
all selfish DNA would want to do.

But the whole mechanism for all this is in the female genome. So how
does the male genome manage to assert its advantage when the female
derives no advantage from the association?

The male's DNA benefits from the sperm being slaves to the queen.-a It doesn't have to assert any advantage it just has to successfully
replicate, and the females empty (0N) eggs are used to replicate the
male's DNA.

Yes, but how does the queen benefit from this?

My guess that initially the hybridization between the two species
selected for queens prone to non disjunction in Meiosis I.-a These
defective queens would have been the ones to benefit from mating with another species whose DNA they didn't need.

What benefit?

For normal matings the
triploids produced would have difficulty reproducing or there might have been a lot of dead triploid embryos produced, so the queens prone to non disjunction would have been selected against.

The question isn't why the queens mate with non-conspecifics. The
question is why they mate at all.

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 06/09/2025 23:42, John Harshman wrote:

On 9/6/25 11:00 AM, RonO wrote:

On 9/6/2025 9:37 AM, John Harshman wrote:

On 9/6/25 6:51 AM, RonO wrote:

On 9/6/2025 5:23 AM, Ernest Major wrote:

On 06/09/2025 03:09, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-
hatch- two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian >>>>>>>> harvester ant (Messor ibericus) takes the weirdness to the next >>>>>>>> level. Queens mate with males of another species and then clone >>>>>>>> them, researchers report today in Nature, which means this ant >>>>>>>> is the only known organism that propagates two species by
itself. Evolutionary biologist Jonathan Romiguier of the
University of Montpellier, who led the team, calls M. ibericus >>>>>>>> rCLin a sense, the most complex, colonial life form we know of so >>>>>>>> far.rCY

The researchers think the M. ibericus queens are cloning the M. >>>>>>>> structor males. The queens allow the M. structor sperm to enter >>>>>>>> their eggs, but at some point they remove their own genes from >>>>>>>> the eggrCOs nucleus to prevent fertilization, thereby ensuring the >>>>>>>> egg develops into a male and not a sterile female worker. By
keeping these cloned males on hand, M. ibericus ant colonies can >>>>>>>> live in places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they >>>>>>> inviable? What happens to unfertilized eggs with M. ibericus
genomes? Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is
that since the ants remain highly polymorphic (not inbred) they
can go through genetic recombination, but there is a non
disjunction at Meiosis I so you get one empty egg cell and one
tetraploid egg cell. This would make half the possible eggs empty >>>>>> (0N).-a At meiosis two you separate the two chromatids and end up >>>>>> with diploid eggs that has recombined queen chromosomes, so you do >>>>>> not lose the genetic heterozygousity found in the queen.-a Eggs she >>>>>> allows to be fertilized produce triploid (probably inviable)
zygotes and haploid male M. structor males.-a The triploids would >>>>>> die and account for not all male eggs hatching.-a The unfertilized >>>>>> eggs produce normal diploid female M. ibericus ants or empty
eggs.-a I do not know how many empty eggs are produced because they >>>>>> may preferentially become polar bodies. You have 3 polar bodies
and one large egg cell as products of female meiosis.-a For males >>>>>> all the cells turn into sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid
the ants would become highly inbred and would soon be pure M.
structor DNA.

It could be a case of Dawkin's selfish DNA.-a The DNA of the queen >>>>>> devised a means of perpetuating its genetics in a way that
prevented inbreeding depression, while being able to generate new >>>>>> segregating genetic diversity among the daughter queens if the
ants still have genetic recombination before Meiosis I.

I don't find obvious which species is doing the exploiting. It
reminds me of androgenesis in Cupressus dupreziana. That species
produces diploid pollen, which after fertilisation somehow disposes >>>>> of the maternal genome, thereby cloning the male parent. (With the
possible exception of plastid and mitochondrial genomes, but the
default is paternal inheritance of plastids in Pinaceae and of both >>>>> in other conifers.)

It also reminds me of Rana esculentus.

As I just commented to Harshman this conforms to selfish DNA for
both species.-a The M. structor genome is cloned each generation, and >>>> the M. ibericus queen's genome is transmitted to the next generation
without inbreeding or mixing with someone elses DNA.-a Both genomes
are maintained intact and not hybrid in a single population.-a Both
genomes get propagated and preserve their genetic identity.-a That is >>>> all selfish DNA would want to do.

But the whole mechanism for all this is in the female genome. So how
does the male genome manage to assert its advantage when the female
derives no advantage from the association?

The male's DNA benefits from the sperm being slaves to the queen.-a It
doesn't have to assert any advantage it just has to successfully
replicate, and the females empty (0N) eggs are used to replicate the
male's DNA.

Yes, but how does the queen benefit from this?

My guess that initially the hybridization between the two species
selected for queens prone to non disjunction in Meiosis I.-a These
defective queens would have been the ones to benefit from mating with
another species whose DNA they didn't need.

What benefit?

For normal matings the triploids produced would have difficulty
reproducing or there might have been a lot of dead triploid embryos
produced, so the queens prone to non disjunction would have been
selected against.

The question isn't why the queens mate with non-conspecifics. The
question is why they mate at all.

Having skimmed the Nature paper ( https://www.nature.com/articles/s41586-025-09425-w ) ...

Denote the Messor ibericus genome as I, and the Messor structor genome
as S.

M. ibericus queens have diploid II genomes. M. ibericus workers have
diploid IS genomes. M. ibericus produces males with either I or S
haploid genomes (and M. ibericus mitomes in both cases).

Presumably the advantage to the Messor ibericus queen is that the hybrid workers are more heterozygous, and heterosis leads to an adaptively
superior colony (allowing a greater production of Messor ibericus
daughter queens?) The production of M. ibericus males maintains genetic diversity within the M. ibericus queen population, and the production of
M. structor males allows the production of hybrid workers (a phenomenon
that occurs in other ant species, and which is called sperm parasitism)
in the absence of co-occuring M. structor colonies.
--
alias Ernest Major

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 9/6/2025 5:37 PM, John Harshman wrote:

On 9/6/25 10:48 AM, RonO wrote:

On 9/6/2025 9:09 AM, John Harshman wrote:

On 9/6/25 6:40 AM, RonO wrote:

On 9/5/2025 10:53 PM, John Harshman wrote:

On 9/5/25 7:09 PM, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-
hatch- two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian >>>>>>>> harvester ant (Messor ibericus) takes the weirdness to the next >>>>>>>> level. Queens mate with males of another species and then clone >>>>>>>> them, researchers report today in Nature, which means this ant >>>>>>>> is the only known organism that propagates two species by
itself. Evolutionary biologist Jonathan Romiguier of the
University of Montpellier, who led the team, calls M. ibericus >>>>>>>> rCLin a sense, the most complex, colonial life form we know of so >>>>>>>> far.rCY

The researchers think the M. ibericus queens are cloning the M. >>>>>>>> structor males. The queens allow the M. structor sperm to enter >>>>>>>> their eggs, but at some point they remove their own genes from >>>>>>>> the eggrCOs nucleus to prevent fertilization, thereby ensuring the >>>>>>>> egg develops into a male and not a sterile female worker. By
keeping these cloned males on hand, M. ibericus ant colonies can >>>>>>>> live in places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they >>>>>>> inviable? What happens to unfertilized eggs with M. ibericus
genomes? Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is
that since the ants remain highly polymorphic (not inbred) they
can go through genetic recombination, but there is a non
disjunction at Meiosis I so you get one empty egg cell and one
tetraploid egg cell. This would make half the possible eggs empty >>>>>> (0N).-a At meiosis two you separate the two chromatids and end up >>>>>> with diploid eggs that has recombined queen chromosomes, so you do >>>>>> not lose the genetic heterozygousity found in the queen.-a Eggs she >>>>>> allows to be fertilized produce triploid (probably inviable)
zygotes and haploid male M. structor males.-a The triploids would >>>>>> die and account for not all male eggs hatching.-a The unfertilized >>>>>> eggs produce normal diploid female M. ibericus ants or empty
eggs.-a I do not know how many empty eggs are produced because they >>>>>> may preferentially become polar bodies. You have 3 polar bodies
and one large egg cell as products of female meiosis.-a For males >>>>>> all the cells turn into sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid
the ants would become highly inbred and would soon be pure M.
structor DNA.

That's certainly a possible mechanism. But in that case what's the
point of having males at all? What you describe is just
parthenogenesis. Now it's true that some parthenogenetic species
(Sceloporus lizards, for example) still mate with males of some
other species, necessary for reproduction for some reason even
though the male contributes nothing to the next generation. Perhaps >>>>> this is such a situation, though I don't know why mating is required. >>>>

Some animals like some of the triploid parthenogenetic lizards need
to mate in order to stimulate egg production.-a The lizards do not
use the male sperm, but produce parthenogenetic offspring with the
female's triploid genetics.

As I said. But what's the point of the male for the ants?

My guess is that the female ants need to be mated before they further
develop into egg laying machines.-a This allows this species to
maintain the genome of a single queen to be perpetuated, but the
daughters are not clones.-a Meiotic recombination would scramble the
queens chromosomes so that she would maintain an amazing amount of
genetic variation among her progeny so that further adaptation could
occur.-a If they just kept mating sibs together in order to maintain
the queens genetics they would probably end up with an inbred mess and
die out.

One diploid individual is an extreme bottleneck, and couldn't contain
all that much genetic variation. And recombination within a single
diploid genome isn't generating much new variation.

This one did because these populations of M. ibericus remain highly polymorphic even though the male's DNA is clonal. My guess is that
genetic recombination occurs before the non disjunction and that the
most heterozygous females were selected by how well their colonies did.
Highly heterozygous females would produce highly polymorphic non
disjunction offspring. This is essentially an instant speciation from
M. ibericus. Each new colony is essentially a new lineage (species) no
longer interbreeding with the others, but they maintain a high degree of
the M. ibericus genetic variation likely due to selection for
heterozygousity in the queens.

The ant male DNA also benefits from this arrangement.-a Clonal
offspring are produce that keep perpetuating the male's DNA each
generation.-a It is pretty much a win win for the selfish DNA.-a The
DNA of two divergent species is preserved in one population, and
they are preserved as intact genomes.

Again, what benefit does the female genome derive from this process?
Why wouldn't evolution dispense with the male, unless it has some
essential function that's hard to get rid of?

The selfish DNA proposal would have this situation selected for
because it transfers the individual's DNA without having to mix with
other DNA.

The queen's DNA shouldn't care what happens to the male's DNA. And the male's DNA has no power to influence its own reproduction. So we still
have to ask why the queen would bother mating at all.

You can think of each being selfish parasites on the other. The queen
doesn't need the males DNA, but the male doesn't care because it can use
the empty eggs that the queen has to produce in order to reproduce
herself, and the queen needs to allow the parasitism because she needs
to mate with a male. They prey on each other to reproduce themselves.

Both the male's and the queen's DNA get transferred intact to the next
generation, and the queen is able to do this in a way that maintains
high genetic variation among her offspring without having to share the
success with someone else.

Yet this ability does not depend on preserving the male's genome or upon mating with a male.

But the way that the queen reproduces herself requires a male, and also produces empty eggs that the male can use to reproduce itself. The
species does need the male DNA to produce males for the next generation,
but that DNA is not used in the normal way by the queen to reproduce her
DNA.

I had assumed that females result from fertilized eggs, each with a >>>>> full, haploid M. structor genome and a haploid M. ibericus genome.
Of course the problem with that is how you would get genetic
divergence between the species, given recombination during meiosis.

You might get recombination if the chromosomes match up, but after
repeated generations using the cloned male genome the species would
eventually become inbred M. structor, so there would be a species
switch eventually.-a The first generation you get 50% M. structor
DNA. The next generation you become 75% M. structor DNA.-a The next
generation you get 87.5% M. Structor offspring etc..-a So when they
claimed that the genomes remained highly polymorphic and M. ibericus
I assumed that any hybrids had to be dead.

It could be a case of Dawkin's selfish DNA.-a The DNA of the queen >>>>>> devised a means of perpetuating its genetics in a way that
prevented inbreeding depression, while being able to generate new >>>>>> segregating genetic diversity among the daughter queens if the
ants still have genetic recombination before Meiosis I.

How can you get or retain much diversity? Wouldn't that result in
complete homozygosity after only a few generations? The male is
contributing nothing.

If the nondisjuction event occurs in meiosis I, meiosis II results
in chromatid splitting in a full diploid genome.-a I called this a
tetraploid egg because that is what the composition of the egg cell
would be if you started with a tetraploid and had a normal Meiosis I
separation of homologous chromosomes.

Since recombination occurs before Meiosis I you maintain genetic
diversity and do not just produce clones.-a When the chromatids split >>>> at Meiosis II, recombined genetically unique chromosomes can go into
each egg cell.

I used to make my genetic students understand Meiosis.-a I would tell >>>> them that if they understood meiosis that they would understand
Mendelian genetics.

Nevertheless, you start with a single diploid individual, and that's
limited genetic diversity. Recombination within a single genome can
only introduce a little, and mutation a little. Keeping in mind that
the effective population size (queens only) is likely to be small,
how is any significant diversity maintained?

Mutation rate is essentially the same because both copies of the
genome of the 2N species is mutated every generation, and only half is
transferred to the next generation.-a In this case the 2N is
transferred to the next generation, so it is the same as having
another half mutated genome incorporated instead.-a The queen is highly
heterozygous and is segregating a lot of genetic variation, but this
variation is not segregating normally.

Is the queen in fact highly heterozygous? What maintains heterozygosity? Does recombination, in most cases, even produce selectable variation?
Most of the genome is junk, and the bits that aren't mostly don't care
which chromatid they're on or which nearby variants are on. I can see crossover within an exon possibly producing a new, functionally
different allele, but how often would even that happen?

Selection. If recombination doesn't occur normally then all the queens
would be highly heterozygous clones. If recombination does occur then
the queen doesn't produce clones, but new chromosomal haplotype
combinations each generation, and it sounds like the most heterozygous
queens get selected because they produce the most successful highly polymorphic colonies.

Instead of transferring half of the variation to the next generation,
she is transferring it all, but there are a near infinite number
variant packages that she can transfer when you consider genetic
recombination and new mutation.-a Every meiosis she generates a whole
new set of chromosomal haplotypes to pass on to her offspring.

Yes, but how many of them have any functional differences. The genome is transferred with all the same bases, just swapped to different
chromatids now and then. Heterozygosity increases only through mutation.

Probably a lot of the different combinations have functional
differences, and the new combinations around the chromosomal break
points would persist with decreasing size for many generations. The
drawback to this is as you and I previously pointed out you lose the
abilty to acquire more genetic variation by outcrossing, but a selfish
DNA success doesn't look that far into the future. Parthenogenetic
species like this might be doomed to extinction unless they can produce
enough new colonies to keep selecting the most fit for their current environment. This is true for all parthenogenetic species that produce basically clonally. Those that do reproduce clonally have to rely on
new mutation to save them under changing selection pressure. This case started with enough genetic variation to keep producing highly
polymorphic populations.

What is lost is the ability to gain new genetic variants due to normal
sexual reproduction.-a In this case the queen posesses a highly
polymorphic genome that has been repeatedly tested and won out to
create an expanding population with the same starting genetics.

Again, do you actually know that the genome is highly polymorphic,
whatever that means in an effective population size of one?\

The authors claim that the parthenogenetic species is highly
polymorphic, but my guess is that it may not be as polymorphic as the
sexually reproducing outcrossing species. The parthenogenetic colonies
may be as polymorphic as any individual normal M. ibericus colony. It
sounds like M. ibericus relies on inbreeding in that male and female
sibs create the new colonies. I would expect the normal amount of
genetic variation in an M. ibericus colony to be low, and they normally
rely on the most polymorphic sib pairing to produce successful colonies.
the normal M. ibericus may also reproduce selfishly and not want to reproduce someone else's DNA, but the species has to pay the price for
doing inbreeding within a family. Non disjunction is better than sib
matings for keeping the DNA within the family.

Each new queen would have a different combination of genetic variation
inherited from the original queen.-a Any combination that isn't as
successful would be out competed.

I just can't see recombination of this sort as producing much selectable variation.

Position effect is when a genes position on the chromosome is associated
with how well it functions. When you change the linkage you change what alleles of flanking genes exist to affect the expression of alleles
nearby. Just think about recombination around a deleterious loci. One
of the models for heterosis is linkage to deleterious loci. The loci
flanking a deleterious loci may have selective advantage, but
heterozygousity (hybrid vigor) is maintained because homozygotes are
selected against. Recombination shuffles the variants around the
deleterious loci. Gene interaction is likely very important (everything
has to work with everything else that is working) and it has long been
posited that the arrangement of alleles along the chromosome was
important (often genes involved in the same biochemical pathway or
function in the organism are found in close linkage on the same
chromosome). Closely linked loci are more likely to be inherited
together, so if you create a linkage between two variant alleles that
have some selective advantage together the progeny are more likely to
inherit both of those alleles. If recombination still occurs in these
queens they can produce many offspring with new linkage arrangements.
New advantageous linkage arrangements are more likely be be inherited together. They can change the linkage with a deleterious allele so that
the advantageous flanking alleles can be fixed in the population and the deleterious allele can eventually be lost.
Ron Okimoto

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 9/6/2025 5:42 PM, John Harshman wrote:

On 9/6/25 11:00 AM, RonO wrote:

On 9/6/2025 9:37 AM, John Harshman wrote:

On 9/6/25 6:51 AM, RonO wrote:

On 9/6/2025 5:23 AM, Ernest Major wrote:

On 06/09/2025 03:09, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs-
hatch- two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian >>>>>>>> harvester ant (Messor ibericus) takes the weirdness to the next >>>>>>>> level. Queens mate with males of another species and then clone >>>>>>>> them, researchers report today in Nature, which means this ant >>>>>>>> is the only known organism that propagates two species by
itself. Evolutionary biologist Jonathan Romiguier of the
University of Montpellier, who led the team, calls M. ibericus >>>>>>>> rCLin a sense, the most complex, colonial life form we know of so >>>>>>>> far.rCY

The researchers think the M. ibericus queens are cloning the M. >>>>>>>> structor males. The queens allow the M. structor sperm to enter >>>>>>>> their eggs, but at some point they remove their own genes from >>>>>>>> the eggrCOs nucleus to prevent fertilization, thereby ensuring the >>>>>>>> egg develops into a male and not a sterile female worker. By
keeping these cloned males on hand, M. ibericus ant colonies can >>>>>>>> live in places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they >>>>>>> inviable? What happens to unfertilized eggs with M. ibericus
genomes? Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is
that since the ants remain highly polymorphic (not inbred) they
can go through genetic recombination, but there is a non
disjunction at Meiosis I so you get one empty egg cell and one
tetraploid egg cell. This would make half the possible eggs empty >>>>>> (0N).-a At meiosis two you separate the two chromatids and end up >>>>>> with diploid eggs that has recombined queen chromosomes, so you do >>>>>> not lose the genetic heterozygousity found in the queen.-a Eggs she >>>>>> allows to be fertilized produce triploid (probably inviable)
zygotes and haploid male M. structor males.-a The triploids would >>>>>> die and account for not all male eggs hatching.-a The unfertilized >>>>>> eggs produce normal diploid female M. ibericus ants or empty
eggs.-a I do not know how many empty eggs are produced because they >>>>>> may preferentially become polar bodies. You have 3 polar bodies
and one large egg cell as products of female meiosis.-a For males >>>>>> all the cells turn into sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid
the ants would become highly inbred and would soon be pure M.
structor DNA.

It could be a case of Dawkin's selfish DNA.-a The DNA of the queen >>>>>> devised a means of perpetuating its genetics in a way that
prevented inbreeding depression, while being able to generate new >>>>>> segregating genetic diversity among the daughter queens if the
ants still have genetic recombination before Meiosis I.

I don't find obvious which species is doing the exploiting. It
reminds me of androgenesis in Cupressus dupreziana. That species
produces diploid pollen, which after fertilisation somehow disposes >>>>> of the maternal genome, thereby cloning the male parent. (With the
possible exception of plastid and mitochondrial genomes, but the
default is paternal inheritance of plastids in Pinaceae and of both >>>>> in other conifers.)

It also reminds me of Rana esculentus.

As I just commented to Harshman this conforms to selfish DNA for
both species.-a The M. structor genome is cloned each generation, and >>>> the M. ibericus queen's genome is transmitted to the next generation
without inbreeding or mixing with someone elses DNA.-a Both genomes
are maintained intact and not hybrid in a single population.-a Both
genomes get propagated and preserve their genetic identity.-a That is >>>> all selfish DNA would want to do.

But the whole mechanism for all this is in the female genome. So how
does the male genome manage to assert its advantage when the female
derives no advantage from the association?

The male's DNA benefits from the sperm being slaves to the queen.-a It
doesn't have to assert any advantage it just has to successfully
replicate, and the females empty (0N) eggs are used to replicate the
male's DNA.

Yes, but how does the queen benefit from this?

The queens DNA benefits because the female likely requires being mated
before developing into an egg laying machine. If no male is around no
eggs get produced. No M. ibericus progeny.

My guess that initially the hybridization between the two species
selected for queens prone to non disjunction in Meiosis I.-a These
defective queens would have been the ones to benefit from mating with
another species whose DNA they didn't need.

What benefit?

Below. A female prone to nondisjunction is at a disadvantage because
she is producing empty eggs (0N) and 2N egg cells, so she will produce
too many 1N male offspring, and not enough 2N workers and most of the
workers that she does produce may have issues as triploids (they may be inviable). Mating with a different species allowed the female to switch
her egg fertilization strategy. Normally she would produce just enough unfertilized eggs to produce males, but now she doesn't want the male to fertilize the eggs. Her strategy had to switch to preventing male fertilization. Initially the hybrid 2N hybrid progeny (they would have
been produced until a high frequency of non disjunction was attained)
were likely infertile queens, so the non disjuction females would have
been selected for reproduction. This probably allowed selection for
increased frequency of non disjuction and an increse in producing
unfertilized eggs.

For normal matings the triploids produced would have difficulty
reproducing or there might have been a lot of dead triploid embryos
produced, so the queens prone to non disjunction would have been
selected against.

The question isn't why the queens mate with non-conspecifics. The
question is why they mate at all.

The females likely need to mate before completing their development into
egg laying machines, and there is also the selective factors of evolving
an animal prone to a high frequency of non disjunction. Mating with
another species where the hybrid had reproductive issues would select
for the unfertilized non disjunction queens. This would allow for
selection for non disjunction and shifting to producing more
unfertilized eggs.

Ron Okimoto

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From Newsgroup: talk.origins

On 9/6/2025 6:47 PM, Ernest Major wrote:

On 06/09/2025 23:42, John Harshman wrote:

On 9/6/25 11:00 AM, RonO wrote:

On 9/6/2025 9:37 AM, John Harshman wrote:

On 9/6/25 6:51 AM, RonO wrote:

On 9/6/2025 5:23 AM, Ernest Major wrote:

On 06/09/2025 03:09, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs- >>>>>>>>> hatch- two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian >>>>>>>>> harvester ant (Messor ibericus) takes the weirdness to the next >>>>>>>>> level. Queens mate with males of another species and then clone >>>>>>>>> them, researchers report today in Nature, which means this ant >>>>>>>>> is the only known organism that propagates two species by
itself. Evolutionary biologist Jonathan Romiguier of the
University of Montpellier, who led the team, calls M. ibericus >>>>>>>>> rCLin a sense, the most complex, colonial life form we know of so >>>>>>>>> far.rCY

The researchers think the M. ibericus queens are cloning the M. >>>>>>>>> structor males. The queens allow the M. structor sperm to enter >>>>>>>>> their eggs, but at some point they remove their own genes from >>>>>>>>> the eggrCOs nucleus to prevent fertilization, thereby ensuring >>>>>>>>> the egg develops into a male and not a sterile female worker. >>>>>>>>> By keeping these cloned males on hand, M. ibericus ant colonies >>>>>>>>> can live in places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they >>>>>>>> inviable? What happens to unfertilized eggs with M. ibericus
genomes? Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is >>>>>>> that since the ants remain highly polymorphic (not inbred) they >>>>>>> can go through genetic recombination, but there is a non
disjunction at Meiosis I so you get one empty egg cell and one
tetraploid egg cell. This would make half the possible eggs empty >>>>>>> (0N).-a At meiosis two you separate the two chromatids and end up >>>>>>> with diploid eggs that has recombined queen chromosomes, so you >>>>>>> do not lose the genetic heterozygousity found in the queen.-a Eggs >>>>>>> she allows to be fertilized produce triploid (probably inviable) >>>>>>> zygotes and haploid male M. structor males.-a The triploids would >>>>>>> die and account for not all male eggs hatching.-a The unfertilized >>>>>>> eggs produce normal diploid female M. ibericus ants or empty
eggs.-a I do not know how many empty eggs are produced because
they may preferentially become polar bodies. You have 3 polar
bodies and one large egg cell as products of female meiosis.-a For >>>>>>> males all the cells turn into sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid >>>>>>> the ants would become highly inbred and would soon be pure M.
structor DNA.

It could be a case of Dawkin's selfish DNA.-a The DNA of the queen >>>>>>> devised a means of perpetuating its genetics in a way that
prevented inbreeding depression, while being able to generate new >>>>>>> segregating genetic diversity among the daughter queens if the
ants still have genetic recombination before Meiosis I.

I don't find obvious which species is doing the exploiting. It
reminds me of androgenesis in Cupressus dupreziana. That species
produces diploid pollen, which after fertilisation somehow
disposes of the maternal genome, thereby cloning the male parent. >>>>>> (With the possible exception of plastid and mitochondrial genomes, >>>>>> but the default is paternal inheritance of plastids in Pinaceae
and of both in other conifers.)

It also reminds me of Rana esculentus.

As I just commented to Harshman this conforms to selfish DNA for
both species.-a The M. structor genome is cloned each generation,
and the M. ibericus queen's genome is transmitted to the next
generation without inbreeding or mixing with someone elses DNA.
Both genomes are maintained intact and not hybrid in a single
population.-a Both genomes get propagated and preserve their genetic >>>>> identity.-a That is all selfish DNA would want to do.

But the whole mechanism for all this is in the female genome. So how
does the male genome manage to assert its advantage when the female
derives no advantage from the association?

The male's DNA benefits from the sperm being slaves to the queen.-a It
doesn't have to assert any advantage it just has to successfully
replicate, and the females empty (0N) eggs are used to replicate the
male's DNA.

Yes, but how does the queen benefit from this?

My guess that initially the hybridization between the two species
selected for queens prone to non disjunction in Meiosis I.-a These
defective queens would have been the ones to benefit from mating with
another species whose DNA they didn't need.

What benefit?

For normal matings the triploids produced would have difficulty
reproducing or there might have been a lot of dead triploid embryos
produced, so the queens prone to non disjunction would have been
selected against.

The question isn't why the queens mate with non-conspecifics. The
question is why they mate at all.

Having skimmed the Nature paper ( https://www.nature.com/articles/ s41586-025-09425-w ) ...

Denote the Messor ibericus genome as I, and the Messor structor genome
as S.

M. ibericus queens have diploid II genomes. M. ibericus workers have
diploid IS genomes. M. ibericus produces males with either I or S
haploid genomes (and M. ibericus mitomes in both cases).

Presumably the advantage to the Messor ibericus queen is that the hybrid workers are more heterozygous, and heterosis leads to an adaptively
superior colony (allowing a greater production of Messor ibericus
daughter queens?) The production of M. ibericus males maintains genetic diversity within the M. ibericus queen population, and the production of
M. structor males allows the production of hybrid workers (a phenomenon
that occurs in other ant species, and which is called sperm parasitism)
in the absence of co-occuring M. structor colonies.

They think that the non disjuction only applies to eggs that the M.
structor males are produced, but their data is screwy. Their lab egg
analysis was done on 133 eggs (they knew queens laid these eggs). They
only obtained 78 DNA samples. 65 were identified as hybrid, 6 pure
ibericus (male or female they could not tell) and 7 male structor (only structor DNA). They tried to extract DNA from 428 eggs and larva from 5
M. ibericus colonies and ended up with 286 samples that gave results and
they identify 194 hybrid workers, 59 M. ibericus males and queens and 33
M. structor males. They claimed that their analysis would identify
caste, but they didn't find any M. ibericus workers. Apparently workers
could have laid the eggs derived from the 5 colonies, but the first 78
samples could have only been laid by queens because they had isolated
them and collected eggs.

They admit to finding too many M. structor males, but they are not
finding enough pure M. ibericus to account for the males when workers
would also be produced in fertilizations that produce queens and
workers. It looks like the M. ibericus males are not contributing to
the colonies, and about as many queens and male M. ibericus are being
produced as male M. structor. The pure M. ibericus eggs and larva
results could be produced from unfertilized eggs. These eggs would
normally be haploid and produce males, but if an equal number of 2N eggs
had been produced as 0N (needed to produce the M. structor males) the
pure M. ibericus unfertilized eggs would produce 1N males and 2N
females. They probably need to do a ploidy analysis to figure out how
many queens and males are being produced. My guess is that they need to
do a ploidy analysis on the hybrid workers. If the hybrid workers can
produce eggs that they have to worry about, why aren't hybrid queens
produced?

They do not report any results finding non hybrid pure M. ibericus
workers. They just report a lot of colonies with hybrid workers and
claim that the workers have 15 times higher heterozygousity than the
queens that produce them. They do find M. ibericus males in these
colonies, but they do not seem to have any verified progeny among the
eggs tested. The pure M. ibericus could have been produced from
unfertilized eggs. In their figure 1 they have all queens with M.
ibericus genomes and all the workers as being hybrid. The maternal
genome (mitochondria) of the M. structor males is M. ibericus, but they
have pure M. structor nuclear genomes.

They need evidence that the M. ibericus males in the colony are actually producing the queens. It looks like the queens preferentially mate
with the M. structor males, and the M. ibericus males do not contribute
much at all. This seems to indicate that both the queens and the M.
structor males are produced by the same non disjunction event that
produces an empty egg and a 2N egg.

Ron Okimoto

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From Newsgroup: talk.origins

On 9/7/25 8:29 AM, RonO wrote:

On 9/6/2025 5:42 PM, John Harshman wrote:

On 9/6/25 11:00 AM, RonO wrote:

On 9/6/2025 9:37 AM, John Harshman wrote:

On 9/6/25 6:51 AM, RonO wrote:

On 9/6/2025 5:23 AM, Ernest Major wrote:

On 06/09/2025 03:09, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs- >>>>>>>>> hatch- two- species

Some excerpts:

Reproduction is strange in many social insects, but the Iberian >>>>>>>>> harvester ant (Messor ibericus) takes the weirdness to the next >>>>>>>>> level. Queens mate with males of another species and then clone >>>>>>>>> them, researchers report today in Nature, which means this ant >>>>>>>>> is the only known organism that propagates two species by
itself. Evolutionary biologist Jonathan Romiguier of the
University of Montpellier, who led the team, calls M. ibericus >>>>>>>>> rCLin a sense, the most complex, colonial life form we know of so >>>>>>>>> far.rCY

The researchers think the M. ibericus queens are cloning the M. >>>>>>>>> structor males. The queens allow the M. structor sperm to enter >>>>>>>>> their eggs, but at some point they remove their own genes from >>>>>>>>> the eggrCOs nucleus to prevent fertilization, thereby ensuring >>>>>>>>> the egg develops into a male and not a sterile female worker. >>>>>>>>> By keeping these cloned males on hand, M. ibericus ant colonies >>>>>>>>> can live in places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they >>>>>>>> inviable? What happens to unfertilized eggs with M. ibericus
genomes? Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is >>>>>>> that since the ants remain highly polymorphic (not inbred) they >>>>>>> can go through genetic recombination, but there is a non
disjunction at Meiosis I so you get one empty egg cell and one
tetraploid egg cell. This would make half the possible eggs empty >>>>>>> (0N).-a At meiosis two you separate the two chromatids and end up >>>>>>> with diploid eggs that has recombined queen chromosomes, so you >>>>>>> do not lose the genetic heterozygousity found in the queen.-a Eggs >>>>>>> she allows to be fertilized produce triploid (probably inviable) >>>>>>> zygotes and haploid male M. structor males.-a The triploids would >>>>>>> die and account for not all male eggs hatching.-a The unfertilized >>>>>>> eggs produce normal diploid female M. ibericus ants or empty
eggs.-a I do not know how many empty eggs are produced because
they may preferentially become polar bodies. You have 3 polar
bodies and one large egg cell as products of female meiosis.-a For >>>>>>> males all the cells turn into sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid >>>>>>> the ants would become highly inbred and would soon be pure M.
structor DNA.

It could be a case of Dawkin's selfish DNA.-a The DNA of the queen >>>>>>> devised a means of perpetuating its genetics in a way that
prevented inbreeding depression, while being able to generate new >>>>>>> segregating genetic diversity among the daughter queens if the
ants still have genetic recombination before Meiosis I.

I don't find obvious which species is doing the exploiting. It
reminds me of androgenesis in Cupressus dupreziana. That species
produces diploid pollen, which after fertilisation somehow
disposes of the maternal genome, thereby cloning the male parent. >>>>>> (With the possible exception of plastid and mitochondrial genomes, >>>>>> but the default is paternal inheritance of plastids in Pinaceae
and of both in other conifers.)

It also reminds me of Rana esculentus.

As I just commented to Harshman this conforms to selfish DNA for
both species.-a The M. structor genome is cloned each generation,
and the M. ibericus queen's genome is transmitted to the next
generation without inbreeding or mixing with someone elses DNA.
Both genomes are maintained intact and not hybrid in a single
population.-a Both genomes get propagated and preserve their genetic >>>>> identity.-a That is all selfish DNA would want to do.

But the whole mechanism for all this is in the female genome. So how
does the male genome manage to assert its advantage when the female
derives no advantage from the association?

The male's DNA benefits from the sperm being slaves to the queen.-a It
doesn't have to assert any advantage it just has to successfully
replicate, and the females empty (0N) eggs are used to replicate the
male's DNA.

Yes, but how does the queen benefit from this?

The queens DNA benefits because the female likely requires being mated before developing into an egg laying machine.-a If no male is around no
eggs get produced.-a No M. ibericus progeny.

So here we see the benefits to us of reading the actual paper, in which
it turns out that all the workers are hybrids. The M. structor male does indeed contribute to their genomes, which is presumably an advantage in maintaining genetic diversity.

My guess that initially the hybridization between the two species
selected for queens prone to non disjunction in Meiosis I.-a These
defective queens would have been the ones to benefit from mating with
another species whose DNA they didn't need.

What benefit?

Below.-a A female prone to nondisjunction is at a disadvantage because
she is producing empty eggs (0N) and 2N egg cells, so she will produce
too many 1N male offspring, and not enough 2N workers and most of the workers that she does produce may have issues as triploids (they may be inviable).-a Mating with a different species allowed the female to switch her egg fertilization strategy.-a Normally she would produce just enough unfertilized eggs to produce males, but now she doesn't want the male to fertilize the eggs.-a Her strategy had to switch to preventing male fertilization.-a Initially the hybrid 2N hybrid progeny (they would have been produced until a high frequency of non disjunction was attained)
were likely infertile queens, so the non disjuction females would have
been selected for reproduction.-a This probably allowed selection for increased frequency of non disjuction and an increse in producing unfertilized eggs.

All moot, given that the workers are all hybrids.

For normal matings the triploids produced would have difficulty
reproducing or there might have been a lot of dead triploid embryos
produced, so the queens prone to non disjunction would have been
selected against.

The question isn't why the queens mate with non-conspecifics. The
question is why they mate at all.

The females likely need to mate before completing their development into
egg laying machines, and there is also the selective factors of evolving
an animal prone to a high frequency of non disjunction.-a Mating with another species where the hybrid had reproductive issues would select
for the unfertilized non disjunction queens.-a This would allow for selection for non disjunction and shifting to producing more
unfertilized eggs.

Again, moot.

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 9/7/2025 6:09 PM, John Harshman wrote:

On 9/7/25 8:29 AM, RonO wrote:

On 9/6/2025 5:42 PM, John Harshman wrote:

On 9/6/25 11:00 AM, RonO wrote:

On 9/6/2025 9:37 AM, John Harshman wrote:

On 9/6/25 6:51 AM, RonO wrote:

On 9/6/2025 5:23 AM, Ernest Major wrote:

On 06/09/2025 03:09, RonO wrote:

On 9/5/2025 7:56 PM, John Harshman wrote:

On 9/5/25 5:23 PM, Mark Isaak wrote:

https://www.science.org/content/article/ant-queen-lays-eggs- >>>>>>>>>> hatch- two- species

Some excerpts:

Reproduction is strange in many social insects, but the
Iberian harvester ant (Messor ibericus) takes the weirdness to >>>>>>>>>> the next level. Queens mate with males of another species and >>>>>>>>>> then clone them, researchers report today in Nature, which >>>>>>>>>> means this ant is the only known organism that propagates two >>>>>>>>>> species by itself. Evolutionary biologist Jonathan Romiguier >>>>>>>>>> of the University of Montpellier, who led the team, calls M. >>>>>>>>>> ibericus rCLin a sense, the most complex, colonial life form we >>>>>>>>>> know of so far.rCY

The researchers think the M. ibericus queens are cloning the >>>>>>>>>> M. structor males. The queens allow the M. structor sperm to >>>>>>>>>> enter their eggs, but at some point they remove their own >>>>>>>>>> genes from the eggrCOs nucleus to prevent fertilization, thereby >>>>>>>>>> ensuring the egg develops into a male and not a sterile female >>>>>>>>>> worker. By keeping these cloned males on hand, M. ibericus ant >>>>>>>>>> colonies can live in places that lack M. structor.

Unanswered question: why won't M. ibericus males work? Are they >>>>>>>>> inviable? What happens to unfertilized eggs with M. ibericus >>>>>>>>> genomes? Or if there aren't any, why not?

It sounds like no M. ibericus males are produced.-a My guess is >>>>>>>> that since the ants remain highly polymorphic (not inbred) they >>>>>>>> can go through genetic recombination, but there is a non
disjunction at Meiosis I so you get one empty egg cell and one >>>>>>>> tetraploid egg cell. This would make half the possible eggs
empty (0N).-a At meiosis two you separate the two chromatids and >>>>>>>> end up with diploid eggs that has recombined queen chromosomes, >>>>>>>> so you do not lose the genetic heterozygousity found in the
queen.-a Eggs she allows to be fertilized produce triploid
(probably inviable) zygotes and haploid male M. structor males. >>>>>>>> The triploids would die and account for not all male eggs
hatching.-a The unfertilized eggs produce normal diploid female >>>>>>>> M. ibericus ants or empty eggs.-a I do not know how many empty >>>>>>>> eggs are produced because they may preferentially become polar >>>>>>>> bodies. You have 3 polar bodies and one large egg cell as
products of female meiosis.-a For males all the cells turn into >>>>>>>> sperm cells.

If the M. structor sperm were fertilizing eggs that were haploid >>>>>>>> the ants would become highly inbred and would soon be pure M. >>>>>>>> structor DNA.

It could be a case of Dawkin's selfish DNA.-a The DNA of the
queen devised a means of perpetuating its genetics in a way that >>>>>>>> prevented inbreeding depression, while being able to generate >>>>>>>> new segregating genetic diversity among the daughter queens if >>>>>>>> the ants still have genetic recombination before Meiosis I.

I don't find obvious which species is doing the exploiting. It
reminds me of androgenesis in Cupressus dupreziana. That species >>>>>>> produces diploid pollen, which after fertilisation somehow
disposes of the maternal genome, thereby cloning the male parent. >>>>>>> (With the possible exception of plastid and mitochondrial
genomes, but the default is paternal inheritance of plastids in >>>>>>> Pinaceae and of both in other conifers.)

It also reminds me of Rana esculentus.

As I just commented to Harshman this conforms to selfish DNA for
both species.-a The M. structor genome is cloned each generation, >>>>>> and the M. ibericus queen's genome is transmitted to the next
generation without inbreeding or mixing with someone elses DNA.
Both genomes are maintained intact and not hybrid in a single
population.-a Both genomes get propagated and preserve their
genetic identity.-a That is all selfish DNA would want to do.

But the whole mechanism for all this is in the female genome. So
how does the male genome manage to assert its advantage when the
female derives no advantage from the association?

The male's DNA benefits from the sperm being slaves to the queen.
It doesn't have to assert any advantage it just has to successfully
replicate, and the females empty (0N) eggs are used to replicate the
male's DNA.

Yes, but how does the queen benefit from this?

The queens DNA benefits because the female likely requires being mated
before developing into an egg laying machine.-a If no male is around no
eggs get produced.-a No M. ibericus progeny.

So here we see the benefits to us of reading the actual paper, in which
it turns out that all the workers are hybrids. The M. structor male does indeed contribute to their genomes, which is presumably an advantage in maintaining genetic diversity.

Yes, the news article didn't provide what was actually going on. Hybrid workers seem to be made, but not hybrid queens. Apparently haploid M. ibericus males are also produced, and they claim that these males are responsible for the diploid queens, but for some reason they didn't find
and diploid M. ibericus workers among the larva and eggs that they
tested. It looks like the M. ibericus males are duds and not used for
mating. M. ibericus queens are produced, but are they progeny of the M. ibericus males? They claimed that their test would identify caste, but
they only found hybrid workers. These colonies have multiple egg laying queens and multiple males in the colony. I would guess that the colony
males would mate with the queens. So why aren't M. ibericus workers
produced?

They can't seem to get enough DNA from a lot of eggs to do their
analysis. It may be that they have a high frequency of eggs that do not develop. Insect embryos develop in a weird way compared to vertebrates.
By the time they tried to process the eggs for DNA they should have
been filled with thousands of nuclei. They may not be getting the whole
story about what is happening. They know that non disjunction has to
happen to form empty eggs that produce the M. structor males, but they
don't know what happens to the 2N egg cells that would be expected to be produced or the excess 0N egg cells. They claim to be finding too many
M. structor male containing eggs and larva for the numbers of adults in
a colony. That would mean that they are also finding too many male and
queen M. ibericus eggs and larva. There could be some other winnowing
process going on.

My guess that initially the hybridization between the two species
selected for queens prone to non disjunction in Meiosis I.-a These
defective queens would have been the ones to benefit from mating
with another species whose DNA they didn't need.

What benefit?

Below.-a A female prone to nondisjunction is at a disadvantage because
she is producing empty eggs (0N) and 2N egg cells, so she will produce
too many 1N male offspring, and not enough 2N workers and most of the
workers that she does produce may have issues as triploids (they may
be inviable).-a Mating with a different species allowed the female to
switch her egg fertilization strategy.-a Normally she would produce
just enough unfertilized eggs to produce males, but now she doesn't
want the male to fertilize the eggs.-a Her strategy had to switch to
preventing male fertilization.-a Initially the hybrid 2N hybrid progeny
(they would have been produced until a high frequency of non
disjunction was attained) were likely infertile queens, so the non
disjuction females would have been selected for reproduction.-a This
probably allowed selection for increased frequency of non disjuction
and an increse in producing unfertilized eggs.

All moot, given that the workers are all hybrids.

What kind of hybrids, and why aren't any hybrids queens? I looked it up
and triploid ants can be produced, but they are usually due to diploid
sperm fertilizing the eggs. It produces viable workers, but infertile
queens.

They need to do a ploidy analysis on the workers.

One paper that google put up on fire ants claimed that four female ants
(I assume they meant worker ants, the paper had Japanese authors)
produced a range of cell ploidies from the 151 metaphase spreads
obtained from them (they had different numbers of chromosomes in their
cells). The female ants cells could be haploid (35.2%), demi-ploidy
(1.5N: 16.3%) diploid (38.3%), triploid (2.2%), tetraploid (4.4%), other ploidies (3.6%, some octoploids were found). So ants can be pretty
messed up when they are supposed to be diploid females. They claim that
this gives the fire ants some type of advantage.

Ron Okimoto

For normal matings the triploids produced would have difficulty
reproducing or there might have been a lot of dead triploid embryos
produced, so the queens prone to non disjunction would have been
selected against.

The question isn't why the queens mate with non-conspecifics. The
question is why they mate at all.

The females likely need to mate before completing their development
into egg laying machines, and there is also the selective factors of
evolving an animal prone to a high frequency of non disjunction.
Mating with another species where the hybrid had reproductive issues
would select for the unfertilized non disjunction queens.-a This would
allow for selection for non disjunction and shifting to producing more
unfertilized eggs.

Again, moot.

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