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"bushy" human evolution - commentary in Cell

  1. Jul 12, 2018 #1

    jim mcnamara

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    https://www.cell.com/trends/ecology-evolution/fulltext/S0169-5347(18)30117-4


    The authors do not seem to use the term bushy to describe the non-linear evolution of Homo sapiens, but other authors have used it. They use 'African multiregionalism' instead. And also they exclude panmyxia (free for all gene flow as an assumption) in more local populations. The concept is a geographically very widespread series of populations that occasionally interbreed, then remain in isolation, a kind of off again/on again situation. So at any one time in the deep past, there are Homo sapiens populations with very different traits.

    Example from other sources: Homo naledi (250kya)and Homo florisiensis (30kya) are extreme examples of isolation of species of Homo concurrent with H. sapiens.

    http://humanorigins.si.edu/evidence/human-fossils/species/homo-floresiensis
    https://www.newscientist.com/articl...only-250000-years-old-heres-why-that-matters/

    The Cell article shows some nice graphics of traits in skulls moving from one population to another.

    One takeaway concept is that the nice orderly linear progression model of human evolution we learned in elementary school apparently does not apply well. Lots of branches and dead ends is a better match.
     
    Last edited: Jul 13, 2018
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  3. Jul 13, 2018 #2

    Ygggdrasil

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    First, the article was published in the journal Trends in Ecology and Evolution, which is published by Cell Press, but it distinct from the journal Cell.

    Debates over the human evolutionary tree have been discussed previously on PF, for example here https://www.physicsforums.com/threads/human-haplogroups-rule-out-humans-descending-from.930013/

    Here is a good source on the issue: https://www.nature.com/scitable/topicpage/human-evolutionary-tree-417

    In addition to the case for African multiregionalism made by the authors of the commentary piece in Trends in Ecology and Evolution, recent genetic analyses have also found a small percentage of DNA shared between modern Homo sapiens and other hominids found outside of Africa, such as Neanderthals and Denisovans. It remains somewhat unclear whether the mixture represents interbreeding between Homo sapiens and these other hominids or whether the genetic exchanges occurred between ancestors of the different lineages in Africa.

    Hopefully more advanced DNA sequencing technologies and better analytical tools can shed further light on this topic.
     
  4. Jul 15, 2018 #3

    Ygggdrasil

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    Jilia Galway-Witham and Chris Stringer wrote a nice perspective piece on this issue in Science recently: http://science.sciencemag.org/content/360/6395/1296.full (Stringer was also an author on the Trends in Ecology and Evolution piece as well). The piece in Science discusses more about the intermixing on humans with hominids that migrated out of Africa before modern Homo sapiens such as the Neanderthals and Denisovans. The authors write:

     
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