Re: Latest on Neanderthal DNA

On 7/24/24 2:31 PM, RonO wrote:

On 7/21/2024 8:53 AM, RonO wrote:

https://www.science.org/doi/10.1126/science.adi1768
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The article seems to be open access.
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The article claims to be able to identify the origin of fragments of DNA in the ancient and extant genomes that have been sequenced.  Neanderthal and Denisovan genomes show evidence of past introgressions with other Homo populations.  The Denisovans seem to have interbred with a population of Homo that left Africa around a half a million years before them.  Neanderthals apparently interbred with humans from Africa around 250,000 years ago.  Some extant modern humans are descendants of hybrids with Denisovans and have bits of Denisovan DNA and the more archaic Homo genome.  All of the extant humans descended from those that left Africa around 60,000 years ago have bits of Neanderthal DNA in their genomes as well as bits of DNA from the previous migration out of Africa (250,000 years ago) that we got from Neanderthals.
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They have a time line based on their reanalysis of archaic and extant genomes.
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Neanderthals and Denisovans left Africa around 600,000 years ago. Previous estimates range from 500,000 to 800,000 years ago.
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At some point the Denisovans interbred with a population of Homo that they met in Asia.
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Modern humans ventured out of Africa around 250,000 years ago and interbred with Neanderthals, but the African humans population died out or was incorporated into the Neanderthal population.  Previous estimates of this interbreeding event have been between 200,000 and 500,000 years from my recollections.
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Modern humans left Africa and interbred with Neanderthals 50,000 to 60,000 years ago.  The extant modern human populations that made it out of Africa have a couple percent Neanderthal DNA and some of this Neanderthal DNA is the 250,000 year old bits from a previous out of Africa migration.
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There is fossil DNA evidence for other African humans interbreeding with Neanderthal between 60,000 and 250,000 years ago and since the interbreeding 60,000 years ago, but these instances seem to be dead ends that haven't left evidence in extant populations.
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Ron Okimoto
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 Science Daily has an overhyped article on this study.
 https://www.sciencedaily.com/releases/2024/07/240711215541.htm
 Title: 'A history of contact': Geneticists are rewriting the narrative of Neanderthals and other ancient humans
 As far as I can tell nothing has been rewritten.  All the authors have done is refine the timing of events that were already proposed to have happened.  Their estimates also seem to fall within the range given by previous papers that are cited by these authors.

You have to overhype or you don't get into Science. They obviously didn't overhype enough or they would have got into Nature.