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Thread: Neanderthal and Denisovan interbred with an archaic hominin

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    Quote Originally Posted by RP48 View Post
    If I’m understanding it’s implications, it is indicating that Neanderthals and Denisovans developed outside Eurasia, migrated to Eurasia, and once there they interbred with (probably) H. Heidelbergensis which had an extant population in Eurasia at that time.

    Is this on track?
    I think the 1.8 million year old admixture in the combined Neanderthals and Denisovans must be Asian Erectus, or maybe even Antecessor. Heidelberg will then be just the European pre-Neanderthal coming from that branch. And yes, I too think it means Neanderthals and Denisovans developed outside Eurasia.

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    Quote Originally Posted by epoch View Post
    The idea is that Neanderthal had some Anatomical Modern Human (AMH) gene flow which introduced a very ancient human mtDNA and some founder effect caused it to overtake the original mtDNA. That would explain why Miguelons mtDNA is closer to Denisovans. It would also explain that calculated Neanderthal-AMH split is dated older than the calculated split between Neanderthal-mtDNA and AMH mtDNA. It's the γ event from the paper. The Hohlenstein-Stadel Neanderthal study elaborates on it.

    https://www.nature.com/articles/ncomms16046

    It raises highly interesting questions. If mtDNA admixted into Neanderthals earlier than 270,000 years ago but later than 430,000 years ago, where was this AMH population? How did it reach Europe? Jebel Irhoud is the nearest Home Sapiens population, conveniently dated 300,000 years old.
    Not sure that could be founder effect. If it was sevel hundred years after split, mt-DNA of both groups must have changed significantly. So, I would rather believe this was natural selection.

    About 250 000 years ago was anothe Ice Age, so sea levels were lower and probably at the time there where more land ways/short straits from Africa to Europe, not just from NE Africa to Iberia and from what is now Egypt through Asia to Balkans. And we really know very little about Aftrican hominids of the time, definitly not enough to start arguing about what African population is the best candidate to mix with proto-Neanderthals.



    Quote Originally Posted by epoch View Post
    Home Sapiens
    Nice typo

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    Not aware there is evidence that there was an AMH population between 270,000 ya and 400 some thousand ya.

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    Quote Originally Posted by RP48 View Post
    Not aware there is evidence that there was an AMH population between 270,000 ya and 400 some thousand ya.
    Not necessarily entirely modern, but classified as Homo Sapiens
    https://www.nature.com/news/oldest-h...istory-1.22114

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    Quote Originally Posted by artemv View Post
    Not sure that could be founder effect. If it was sevel hundred years after split, mt-DNA of both groups must have changed significantly. So, I would rather believe this was natural selection.
    The population size of neanderthals used to be bigger, as the paper states. There are more papers that more or less picture a highly fluctuating population of Neanderthals. That is an ideal environment for a founder effect.

    https://www.pnas.org/content/early/2.../16/1405138111
    We conclude that the patterns of coding variation in Neandertals differ strongly from those in present-day humans, a fact likely to be the result of differences in their demographic histories. Inferences from the complete Neandertal genome suggest that sometime after 0.5–1.0 Mya, the ancestral Neandertal population decreased in size, whereas the ancestors of present-day
    humans increased in number
    Quote Originally Posted by artemv View Post
    About 250 000 years ago was anothe Ice Age, so sea levels were lower and probably at the time there where more land ways/short straits from Africa to Europe, not just from NE Africa to Iberia and from what is now Egypt through Asia to Balkans. And we really know very little about Aftrican hominids of the time, definitly not enough to start arguing about what African population is the best candidate to mix with proto-Neanderthals.
    Yes, that is probably true. There have been attempts to get some DNA from Jebel Irhoud. If they succeeded with Sima de los Huesos samples, why not with jebel Irhoud samples?
    Last edited by epoch; 06-17-2019 at 08:29 AM.

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    Quote Originally Posted by epoch View Post
    The population size of neanderthals used to be bigger, as the paper states. There are more papers that more or less picture a highly fluctuating population of Neanderthals. That is an ideal environment for a founder effect.
    That's right, decrease in population is usually leads to a founder effect for uniparentals, in case if happlogroups are more or less equally good from evolutionary point of view.

    But if indeed hominids from AMH line lived separately from Neanderthal line for several hundred thousand years, this means there is good chance that one of happlogroups is definitely better than the other one from evolutionary point of view.

    Quote Originally Posted by epoch View Post
    Yes, that is probably true. There have been attempts to get some DNA from Jebel Irhoud. If they succeeded with Sima de los Huesos samples, why not with jebel Irhoud samples?
    Lower temperatures give higher chance to preserve DNA. That's why we have unproportionally high amounts of aDNA from the North. And much less data from tropical areas, with higher population density.
    Jebel Irhoud is to the South from Sima de los Huesos, this means lower chance to get good DNA.
    But let's hope.

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