From Newsgroup: talk.origins

The following is a link to a 42-minute video narrated by Gutsick
Gibbon aka Erika, where she mentions some of the skeletal features
that distinguish humans from other apes and other mammalian species, specifically those that allow our unique bipedal gait: <https://youtu.be/RmcAKrvNjco>
She does this as an introduction to the following recent Nature
article:
<https://www.nature.com/articles/s41586-025-09399-9>
which identifies a suite of genes involved in the embryologic
development of these features, specifically SOX9rCoZNF521rCoPTH1R and RUNX2rCoFOXP1/2.
For example, ancestral ilia were tall and thin, similar to modern
chimpanzees. By rotating the orientation of the ilial growth plate 90
degrees, human ilia became at the same time both wider and shallower.
These changes allowed humans to walk more upright, and provided a
pelvic floor necessary to support internal organs and developing
fetuses previously carried horizontally.
The authors compared the embryologic development of humans, primates,
and mice, in order to identify and document the different embryologic
growth patterns, and to correlate them to genetic changes.
--
To know less than we don't know is the nature of most knowledge
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From Newsgroup: talk.origins

The following is a link to a 42-minute video narrated by Gutsick
Gibbon aka Erika, where she mentions some of the skeletal features
that distinguish humans from other apes and other mammalian species, specifically those that allow our unique bipedal gait: <https://youtu.be/RmcAKrvNjco>
She does this as an introduction to the following recent Nature
article:
<https://www.nature.com/articles/s41586-025-09399-9>
which identifies a suite of genes involved in the embryologic
development of these features, specifically SOX9rCoZNF521rCoPTH1R and RUNX2rCoFOXP1/2.
For example, ancestral ilia were tall and thin, similar to modern
chimpanzees. By rotating the orientation of the ilial growth plate 90
degrees, human ilia became at the same time both wider and shallower.
These changes allowed humans to walk more upright, and provided a
pelvic floor necessary to support internal organs and developing
fetuses previously carried horizontally.
The authors compared the embryologic development of humans, primates,
and mice, in order to identify and document the different embryologic
growth patterns, and to correlate them to genetic changes.
--
To know less than we don't know is the nature of most knowledge
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: talk.origins

On 10/10/2025 1:03 PM, jillery wrote:

The following is a link to a 42-minute video narrated by Gutsick
Gibbon aka Erika, where she mentions some of the skeletal features
that distinguish humans from other apes and other mammalian species, specifically those that allow our unique bipedal gait:

<https://youtu.be/RmcAKrvNjco>

She does this as an introduction to the following recent Nature
article:

<https://www.nature.com/articles/s41586-025-09399-9>

which identifies a suite of genes involved in the embryologic
development of these features, specifically SOX9rCoZNF521rCoPTH1R and RUNX2rCoFOXP1/2.

For example, ancestral ilia were tall and thin, similar to modern chimpanzees. By rotating the orientation of the ilial growth plate 90 degrees, human ilia became at the same time both wider and shallower.
These changes allowed humans to walk more upright, and provided a
pelvic floor necessary to support internal organs and developing
fetuses previously carried horizontally.

The authors compared the embryologic development of humans, primates,
and mice, in order to identify and document the different embryologic
growth patterns, and to correlate them to genetic changes.

I've always expected that a single genetic event caused the hip
deformation. Like the paper claims two things need to happen. The
ilium needs to shorten and and the pelvis has to bend at a 90 degree
angle. If the ilium isn't shorter you would end up with that part of
the hip protruding from the back of the animal when the pelvis bends at
a 90 degree angle. I always expected that the pelvis deformation (the
90 degree bend) also resulted in messed up development of the ilium.
The 90 degree deformation isn't that bad a handicap for an arboreal brachiator. Evidence indicates that the common ancestor with chimps and humans was not yet a knuckle walker so it was likely more aboreal like a gibbon. The bent hip would force the animal to be more upright, and is thought to have some advantage in climbing narrow trunk trees (recall
humans climbing coconut palms). It also allows for more strength in
standing on lower branches while hanging onto another branch. This
would allow a larger animal to exploit the same resources as a smaller primate.

The other hip and muscular variation would occur as our ancestors
started walking on the ground. Modifications like the modern human
adaptation of the hip to pass infants with larger heads through the
available opening would have evolved as infants were born with larger
and larger heads as the cranial capacity increased in Homo erectus.

Ron Okimoto

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