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  1. #1
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    3 members found this post helpful.

    Origins of Modern Human Ancestry

    See:
    https://www.nature.com/articles/s41586-021-03244-5
    for a very interesting read.


    • Anders Bergström,
    • Chris Stringer,
    • Mateja Hajdinjak,
    • Eleanor M. L. Scerri &
    • Pontus Skoglund


    "New finds in the palaeoanthropological and genomic records have changed our view of the origins of modern human ancestry. Here we review our current understanding of how the ancestry of modern humans around the globe can be traced into the deep past, and which ancestors it passes through during our journey back in time. We identify three key phases that are surrounded by major questions, and which will be at the frontiers of future research. The most recent phase comprises the worldwide expansion of modern humans between 40 and 60 thousand years ago (ka) and their last known contacts with archaic groups such as Neanderthals and Denisovans. The second phase is associated with a broadly construed African origin of modern human diversity between 60 and 300 ka. The oldest phase comprises the complex separation of modern human ancestors from archaic human groups from 0.3 to 1 million years ago. We argue that no specific point in time can currently be identified at which modern human ancestry was confined to a limited birthplace, and that patterns of the first appearance of anatomical or behavioural traits that are used to define Homo sapiens are consistent with a range of evolutionary histories."


    Non si fa il proprio dovere perchè qualcuno ci dica grazie, lo si fa per principio, per se stessi, per la propria dignità. Oriana Fallaci

  2. #2
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    Did Humans originate in an African-South Eurasian Central Zone?

    South Asians have huge diversity in their relationship to early hominids (see stats below).
    Africans look connected to Eurasians in two ways, a migration path from East Africa to NW India and also a migration path from SW Asia into Africa.
    Evolution is much faster when populations move to new areas. Could Humans have evolved due to constant movement and migration around Northern Africa and South Eurasia in an anti-clockwise direction?
    The d stat below shows the affinity of X to Y (Vindija Neanderthal) vs Z (Denisova). Everyone is closer to Vindija vs Denisova but the South Asians are not uniform at all and have huge variation in the d (result of the calc). In comparison the bolded shows how close Europeans are to each other.

    W X Y Z d stdErr Z
    Chimp.REF ONG.SG Vindija.DG Denisova.DG -0.127 0.0124 -10.2
    Chimp.REF Jatt Vindija.DG Denisova.DG -0.126 0.0131 -9.65
    Chimp.REF PUN.SG Vindija.DG Denisova.DG -0.126 0.014 -8.97
    Chimp.REF GujaratiD Vindija.DG Denisova.DG -0.122 0.0117 -10.4
    Chimp.REF Han Vindija.DG Denisova.DG -0.122 0.0118 -10.3
    Chimp.REF Control Vindija.DG Denisova.DG -0.121 0.0127 -9.52
    Chimp.REF UBR.SG Vindija.DG Denisova.DG -0.121 0.0116 -10.5
    Chimp.REF GujaratiA Vindija.DG Denisova.DG -0.12 0.0116 -10.4
    Chimp.REF ITU.SG Vindija.DG Denisova.DG -0.12 0.0114 -10.5
    Chimp.REF Kalash Vindija.DG Denisova.DG -0.119 0.0114 -10.4
    Chimp.REF PJL.SG Vindija.DG Denisova.DG -0.119 0.0114 -10.4
    Chimp.REF Balochi Vindija.DG Denisova.DG -0.118 0.0112 -10.5
    Chimp.REF Sindhi_Pakistan Vindija.DG Denisova.DG -0.118 0.0114 -10.4
    Chimp.REF Pathan Vindija.DG Denisova.DG -0.118 0.0114 -10.3
    Chimp.REF Ror Vindija.DG Denisova.DG -0.118 0.012 -9.8
    Chimp.REF Mongol Vindija.DG Denisova.DG -0.118 0.0116 -10.1
    Chimp.REF Iranian Vindija.DG Denisova.DG -0.116 0.0114 -10.1
    Chimp.REF GujaratiB Vindija.DG Denisova.DG -0.115 0.0116 -9.97
    Chimp.REF English Vindija.DG Denisova.DG -0.115 0.0116 -9.89
    Chimp.REF French Vindija.DG Denisova.DG -0.115 0.0113 -10.2
    Chimp.REF Russian Vindija.DG Denisova.DG -0.115 0.0113 -10.2
    Chimp.REF RAJ.SG Vindija.DG Denisova.DG -0.114 0.0118 -9.67
    Chimp.REF Greek Vindija.DG Denisova.DG -0.113 0.0113 -10
    Chimp.REF Saudi Vindija.DG Denisova.DG -0.112 0.0115 -9.74
    Chimp.REF Mbuti Vindija.DG Denisova.DG -0.111 0.011 -10.1
    Chimp.REF Papuan Vindija.DG Denisova.DG -0.1 0.0122 -8.22
    Chimp.REF Yoruba Vindija.DG Denisova.DG -0.0995 0.011 -9.07


    The below f3(sample, Chimp; Gorilla) shows the shared drift between populations and Chimp, with Gorilla as a reference (outgroup). It shows Africans with the most, followed by South Asians, especially Gujaratis. Can this be read as a connection between Africa and Eurasia through East Africa and Gujarat in India with geneflow going South to North. I used Chimp here because Yoruba is skewed towards West Asia (due to back migrations?), see next section and this may also affect other Africans. I know this is 'weird' calculation but the results do seem credible and it does rank populations in a geographically meaningful way (Indian Gujaratis closest to Africans, with our most distant relative as an outgroup)

    Mbuti Chimp.REF Gorilla.REF 17 0.372 45.6 77332
    Yoruba Chimp.REF Gorilla.REF 16.7 0.355 46.9 89308
    GujaratiB Chimp.REF Gorilla.REF 16.3 0.344 47.3 79192
    GujaratiMuslim Chimp.REF Gorilla.REF 16.3 0.376 43.5 51980
    Kalash Chimp.REF Gorilla.REF 16.2 0.345 47.1 84255
    Iranian Chimp.REF Gorilla.REF 16.2 0.337 48 88944
    Saudi Chimp.REF Gorilla.REF 16.2 0.344 47.1 82632
    Jatt Chimp.REF Gorilla.REF 16.2 0.381 42.4 51663
    Pathan Chimp.REF Gorilla.REF 16.1 0.339 47.5 87030
    GujaratiD Chimp.REF Gorilla.REF 16.1 0.347 46.5 78459
    English Chimp.REF Gorilla.REF 16.1 0.34 47.4 83963
    ITU.SG Chimp.REF Gorilla.REF 16 0.337 47.4 88704
    Han Chimp.REF Gorilla.REF 16 0.345 46.4 84825
    BIR.SG Chimp.REF Gorilla.REF 15.8 0.353 44.7 73392
    ONG.SG Chimp.REF Gorilla.REF 15.7 0.363 43.3 62378


    The below shows affinity to Yoruba. Saudi and Iran are much higher here than in the above, so it looks like there is a connection going from West Asia into Africa that is bringing Yoruba closer to Eurasians than Mbuti. Also, this is so pronounced that Yoruba is actually closer to Eurasians than to Mbuti (with Chimp as an outgroup).

    A B C f3 stderr Zscore nsnps
    Saudi Yoruba Chimp.REF 173.469078 0.83467 207.83 97367
    GujaratiB Yoruba Chimp.REF 173.256023 0.830172 208.699 97234
    Iranian Yoruba Chimp.REF 173.233672 0.812747 213.146 98169
    English Yoruba Chimp.REF 173.155891 0.8273 209.302 97808
    Pathan Yoruba Chimp.REF 173.061386 0.813003 212.867 97985
    GujaratiD Yoruba Chimp.REF 173.057729 0.83851 206.387 97132
    Kalash Yoruba Chimp.REF 172.987336 0.822178 210.401 97720
    ITU.SG Yoruba Chimp.REF 172.873579 0.808437 213.837 98141
    Han Yoruba Chimp.REF 172.696153 0.823571 209.692 97706
    Jatt Yoruba Chimp.REF 172.497426 0.907935 189.989 95283
    BIR.SG Yoruba Chimp.REF 172.422746 0.845454 203.941 96617
    GujaratiMuslim Yoruba Chimp.REF 172.405889 0.918324 187.74 95860
    ONG.SG Yoruba Chimp.REF 171.236629 0.87319 196.105 96038
    Mbuti Yoruba Chimp.REF 157.057917 0.800474 196.206 95224


    Finally, looking at affinity to ancient hominids, it seems the populations at the corners of the world have the most. Papuans have a lot, so do Northern Europeans apparantly, and Mbuti seems to have quite a bit too. South Asians seems to be most distant in general to ancient hominids. In the first calc above, we are comparing affinity to Denisova or Vindija, and everyone is closer to Vindija, meaning Vindija is closer to modern humans, so Denisova has more older DNA and Vindija shares more with modern humans which is newer DNA. So Mbuti and Papuans are very low on the list, so they share less DNA with the newer Vindija vs the older Denisova, compared to other modern humans, especially South Asians. Hence it looks like ancient hominid affinity is greatest in the most distant and isolated populations, and then at the outer parts (Europe and East Asia).
    So taking everything together, does it make sense to say Humans could have evolved due to circular movements between African and Southern Eurasia? Ancient hominid affinity is then greatest in the outer parts, because ancient hominids leaving this central spiral can end up anywhere (East Asia, Siberia, Southern Africa, SE Asia) and then the centre continues to evolve towards modern humans. This explains why people like the Melasians have high Denisova and Neanderthal DNA, because they left the centre at an earlier stage, and so are missing the most recent drift shared by modern humans, also the Mbuti. Basically hominids may be all early humans who left the centre at an earlier stage, but who will also have localization. And humans may not have 'bred' with hominids but the amount of hominid dna in humans could be a result of leaving the centre earlier than others (or the AMH) and hence not sharing the most recent drift of AMH, so that part of the DNA matches hominid instead of AMH.

  3. #3
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    Not sure why the formatting is messed up, but I cant edit it, so just reposting the final paragraphs for readability. Still not great but the below is more readable.

    Finally, looking at affinity to ancient hominids, it seems the populations at the corners of the world have the most. Papuans have a lot, so do Northern Europeans apparantly, and Mbuti seems to have quite a bit too. South Asians seems to be most distant in general to ancient hominids. In the first calc above, we are comparing affinity to Denisova or Vindija, and everyone is closer to Vindija, meaning Vindija is closer to modern humans, so Denisova has more older DNA and Vindija shares more with modern humans which is newer DNA. So Mbuti and Papuans are very low on the list, so they share less DNA with the newer Vindija vs the older Denisova, compared to other modern humans, especially South Asians. Hence it looks like ancient hominid affinity is greatest in the most distant and isolated populations, and then at the outer parts (Europe and East Asia).

    So taking everything together, does it make sense to say Humans could have evolved due to circular movements between African and Southern Eurasia? Ancient hominid affinity is then greatest in the outer parts, because ancient hominids leaving this central spiral can end up anywhere (East Asia, Siberia, Southern Africa, SE Asia) and then the centre continues to evolve towards modern humans. This explains why people like the Melasians have high Denisova and Neanderthal DNA, because they left the centre at an earlier stage, and so are missing the most recent drift shared by modern humans, also the Mbuti. Basically hominids may be all early humans who left the centre at an earlier stage, but who will also have localization. And humans may not have 'bred' with hominids but the amount of hominid dna in humans could be a result of leaving the centre earlier than others (or the AMH) and hence not sharing the most recent drift of AMH, so that part of the DNA matches hominid instead of AMH.




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    we all come from apes. :)

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    2 members found this post helpful.
    Quote Originally Posted by Archangel Michael View Post
    we all come from apes. :)
    Yes, and we are still apes today. Chimps are more closely related to humans than they are to gorillas, and gorillas are more closely related to humans than they are to orang utans. How then can modern humans (and all our ancestors of the past 25 million years) be classified as anything other than a branch of the ape family? The above paper ponders the details of the evolutionary history of one species of ape over the past few hundred thousand years and suggests the history may turn out to be more complex than previously thought.

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