May 28, 2023·edited May 28, 2023Liked by Razib Khan
I'm thinking about a science fiction metaphor. If humans establish interplanetary colonies, they'll be founded by a small fraction of Earth's genetic diversity. If the resultant solar civilization establishes an interstellar colony, it will be founded by a fraction of that fraction. Now imagine subsequent waves of migration off Earth into the solar system, and out of the solar system into e.g. the Centauri system. Anthropologists 100 thousand years hence will see clear lines of ancestry from other systems converging back on the solar system, where things get tangled and confusing, with hints of even greater genetic diversity and deeper introgressions on Earth. Apologizes to Isaac Asimov.
Great stuff! I very much appreciated your chronological narrative of how populations split and recombined. The diagram by itself would have been incomprehensible.
One thing I've been wondering for a while is if geneticists are ever going to publicly argue about re-defining our species / genus classification to reflect that Neanderthals and Denisovans aren't separate species? (At least under the definition of "not producing fertile offspring" that we were taught at school). Is it premature when that's only recently been definitively established? Does it get discussed within the field but not much out of it? (I haven't seen it suggested anyway)
The weakly structured stem article was a great paper. In addition to the paper having a good fit to observed statistics it is also more consistent with archaeology than the other models. It's fascinating that all humans seem to be an almost even split between the stems, with a small majority still being from stem 2. If that is the case then more work needs to be done in west africa, maybe northwest as this is likely where stem 2 was resident and we hardly have any data from there. If we imagine a similar dynamic to the bantu migration then the recoallescences of the stems can be understood with a ready model.
Do the widths of the vertical lines in the main figure indicate relative population densities? Specifically, I wonder if the tiny vertical trace connecting Stem 1 to Stem 1E and Stem 1S indicates a population bottleneck.
The earliest heliocentric models actually had MORE epicycles than the Ptolemaic ones. What they abolished was the equant, which Copernicus hated because he thought all orbits should be constructed from perfect circles (better data would show them to be ellipses).
i feel that the sentence, "There was simply becoming Homo sapiens, a long and gradual process, the evolution, not of the first humans, but the last." has some very unsettling consequences. For example, what does this view say about "human nature" or "Jungian archetypes" ? Absent cataclysmic population bottlenecks (nuclear war or unchecked pandemic anyone ?), how many generations are needed for Homo sapien to evolve into a new better "adapted" species ? (adapted to technology perhaps) ? Keep on writing, it is fascinating.
Was wondering if you had a chance to read my comment from two posts ago about Semitic prehistory and genetics. I’m sorry it’s off-topic but I don’t know of another way to contact you. I hope you can make a post about this topic.
Thank you very much for your careful and thoughtful summary of, and comments on two of my favorite subjects about which to write and teach: evolution and the complexities of biology. It was both enjoyable and thought-provoking. Sincerely, Frederick
I'm thinking about a science fiction metaphor. If humans establish interplanetary colonies, they'll be founded by a small fraction of Earth's genetic diversity. If the resultant solar civilization establishes an interstellar colony, it will be founded by a fraction of that fraction. Now imagine subsequent waves of migration off Earth into the solar system, and out of the solar system into e.g. the Centauri system. Anthropologists 100 thousand years hence will see clear lines of ancestry from other systems converging back on the solar system, where things get tangled and confusing, with hints of even greater genetic diversity and deeper introgressions on Earth. Apologizes to Isaac Asimov.
Great stuff! I very much appreciated your chronological narrative of how populations split and recombined. The diagram by itself would have been incomprehensible.
Razib, when are you going to write a book -- for a general audience I mean
Great article, interesting as always.
One thing I've been wondering for a while is if geneticists are ever going to publicly argue about re-defining our species / genus classification to reflect that Neanderthals and Denisovans aren't separate species? (At least under the definition of "not producing fertile offspring" that we were taught at school). Is it premature when that's only recently been definitively established? Does it get discussed within the field but not much out of it? (I haven't seen it suggested anyway)
Fascinating. Just what I have been waiting for.
The weakly structured stem article was a great paper. In addition to the paper having a good fit to observed statistics it is also more consistent with archaeology than the other models. It's fascinating that all humans seem to be an almost even split between the stems, with a small majority still being from stem 2. If that is the case then more work needs to be done in west africa, maybe northwest as this is likely where stem 2 was resident and we hardly have any data from there. If we imagine a similar dynamic to the bantu migration then the recoallescences of the stems can be understood with a ready model.
Hi Razib,
Do you have anything on the genetic origins of the Mbuti, Bambenga, Bambuti and Batwa (African Foragers)?
Oh, my, that was fantastic. I need to look at those pictures more closely now. We’re a product of layers of paint and DNA is the medium
I enjoyed this piece very much.
Do the widths of the vertical lines in the main figure indicate relative population densities? Specifically, I wonder if the tiny vertical trace connecting Stem 1 to Stem 1E and Stem 1S indicates a population bottleneck.
Any book recommendations on Pre Colonial Africa ?
The earliest heliocentric models actually had MORE epicycles than the Ptolemaic ones. What they abolished was the equant, which Copernicus hated because he thought all orbits should be constructed from perfect circles (better data would show them to be ellipses).
https://entitledtoanopinion.wordpress.com/2011/10/16/dont-rely-on-yglesias-for-kuhns-copernicus-revisionism/
i feel that the sentence, "There was simply becoming Homo sapiens, a long and gradual process, the evolution, not of the first humans, but the last." has some very unsettling consequences. For example, what does this view say about "human nature" or "Jungian archetypes" ? Absent cataclysmic population bottlenecks (nuclear war or unchecked pandemic anyone ?), how many generations are needed for Homo sapien to evolve into a new better "adapted" species ? (adapted to technology perhaps) ? Keep on writing, it is fascinating.
Good work. Very interesting.
The contact author Brenna M. Henn is at UC Davis. Do you know her?
There was a family named Henn who lived down the street from us. I wonder if she is one of them?
She is about the right age. A year older than my oldest.
Dear Razib,
Was wondering if you had a chance to read my comment from two posts ago about Semitic prehistory and genetics. I’m sorry it’s off-topic but I don’t know of another way to contact you. I hope you can make a post about this topic.
Thank you.
Thank you very much for your careful and thoughtful summary of, and comments on two of my favorite subjects about which to write and teach: evolution and the complexities of biology. It was both enjoyable and thought-provoking. Sincerely, Frederick
Razib,
Have you read this article?
https://www.news-medical.net/news/20230521/Unraveling-the-origins-of-humanity-New-research-challenges-single-origin-theory.aspx