Saturday, January 28, 2012

Updates on the Human Journey Project: Spencer Wells


Notes:
  • Estimates YDNA TMRCA to 60 KYA, this is in conflict with Cruciani et. al (2011) :"A Revised Root for the Human Y Chromosomal Phylogenetic Tree: The Origin of Patrilineal Diversity in Africa", where the root of the MSY was estimated to 142 KYA, although Dr. Wells may be talking about CT-M168, it is not clear enough from the video.
  • So far the project has sampled over 1000 different populations around the world, with about 75,000 samples collected from 'indigenous' people, and an additional 415,000 samples from the public who purchased kits.
  • Climate appearing to be a 'key motivator' of migrations.
  • Europe colonized from the south at the end of the ice age from two different directions/sources that acted as a 'Refugium' during the ice age, a Franco-Cantabrian refugium in the southwest of Europe and another refugium in the Southeast (around the Balkans).
  • 'Middle Easterners' from the 'northern area of the Fertile crescent' literally replaced Mesolithic Europeans during the Neolithic revolution, he points to ancient DNA evidence for this.

6 comments:

  1. Y-DNA age estimates have been so severely questioned recently that even someone as fanatic about short chronologies as Dienekes had to admit that the molecular clock is broken.

    Still Cruciani's date is reasonable, Wells' is not. And also I have as of late argued a lot with people who backed their inconsistent opinions on Wells and what would seem to be his old fashioned ideas on the population of East Asia specifically. Instead I have yet to stumble on any too n idea source to Cruciani (everything is possible but he so far he gets my first choice on authoritative respect, seriously).

    "another refugium in the Southeast (around the Balkans)"

    Archaeologically nonsense. I'm glad that the "Iberian refugium" misleading concept has finally yielded to the notion of Franco-Cantabrian region (a notion that I have pushed for in the Internet myself, based on long previously existing literature, of course), which is more correct, but the idea of simple refugia in Europe may well be totally wrong. Whatever the case in the LGM there were many refugia (FC region, Iberia, Italy, High and Mid Danube pockets, Dniepr-Don region...) but not the Balcans: the Balcans, with minor exceptions maybe, were a rather deserted area in the Upper Paleolithic - much as Northern France: they both were arid steppe ecosystems inappropriate for dense inhabitation. But it's not even clear if the Far North (south of the ice sheet, for instance Doggerland, now submerged under the North Sea) was ever fully deserted and how important was immigration after the LGM.

    "'Middle Easterners' from the 'northern area of the Fertile crescent' literally replaced Mesolithic Europeans during the Neolithic revolution, he points to ancient DNA evidence for this".

    Again highly questionable. While there is some serious evidence for discontinuity in Neolithic Central Europe and maybe parts of the Mediterranean, this does not seem extrapolable to all Europe. The new DNA is not necessarily from West Asia (in fact much looks original European, although other does look West Asian indeed) and, intriguingly enough, a modern DNA pool does not seem to appear until the Bronze Age, what implies that the Neolithic peoples did not survive as such but were in turn replaced (if that's what we really get).

    Still in places like Portugal we see (mostly) continuity, not replacement. So... I'm in clear disagreement (and I don't like his face of self-help method salesman: serious academics have a different look).

    ReplyDelete
  2. There are quite a few things I disagree with Wells and his project's results as well, like the fact that they maintain E1b1b originated in the 'Middle East' contrary to almost all publications (Cruciani '04, Cruciani '07, Battaglia '08,etc...) but I would still imagine it to be a monumental task to collect a half a million samples worth of data and try to make some sense of it and catalog it, besides it takes some 'salesmanship' to be able to fund a project of this magnitude, and for that he deserves some credit. Watching his televised programs about 5 years ago was also what initially got me interested in population genetics.

    ReplyDelete
    Replies
    1. I think they may have confused E-M35 for E-M78 on the Genographic project's page, and also some consider Egypt and North Sudan to be the Middle East (even though it really isn't).

      Delete
    2. I don't think it is a confusion, E-M35 nomenclature and its origin in East Africa has been out for well over 7 years now, I would find it odd that this big team would not have access to these studies, and correctly update their maps and its description that clearly specifies E-M35.:

      https://genographic.nationalgeographic.com/genographic/lan/en/atlas.html

      They are likely trying to 'satisfy' some of their customers, as an origin for an exogenous lineage that prevails in Europe would be more 'swallow-able' being from the Middle East rather than from the heart of Africa, especially since this lineage contrasts sharply with the largely homogenous European YDNA pool (R1a,R1b and I).

      Delete
    3. I guess that makes sense. You should consider contacting them on this issue, because it looks rather amateurish for such a large-scale genetic project.

      Delete
    4. By the way, I'm not sure if you have an FTDNA account, but I do, and they also use 'weaselish' descriptions to describe E-M35's origin. Here below I have quoted 3 sites:National Geographic, FTDNA and 23andMe.

      Nat Geo
      "The man who gave rise to marker M35 was born around 20,000 years ago in the Middle East. His descendants were among the first farmers and helped spread agriculture from the Middle East into the Mediterranean region."

      FTDNA
      "With origins in East Africa or the Middle East, E1b1b1 has spread among North and East African populations, the Middle East, and into Europe from the Mediterranean."

      23andMe
      "In northern Africa the most common haplogroups are E1b1b and its many branches. E1b1b itself originated about 22,000 years ago during the height of the last Ice Age. There are several common branches of E1b1b that can be found throughout the Mediterranean, the Near East, and eastern Europe. One of these branches is haplogroup E1b1b1, which originated in a group of people living in eastern Africa."


      Seems to me that 23andMe is the most honest out of the three.
      FTDNA is by the way somewhat connected with Natgeo, the latter often refers you to the former when you want a deep clade test done on your sample, and even some of the 12 marker tests from the public samples collected by Natgeo are done by FTDNA, I believe, or something along those lines.

      Delete