June 5, 2012

H. pylori also made it out of Africa

In our guts.

Out of Africa and back (to some extent) and also again out of Africa into West Eurasia where it mixed with the Eurasian component. All of which is identifiable also in more specifically human markers like Y-DNA or mtDNA.


Ethio Helix has an extensive review of the entry so I'll be most succinct here.



There are more nice images in the paper but this one above probably expresses it all:
  • Hp Africa 2 is found among Southern African natives (Khoisan)
  • Hp Africa 1 is found among West Africans and Bantus (with some penetration in the Khoisan stomachs)
  • Hp NE Africa is found at the Middle and Upper Nile and Lake Chad
  • Hp Europe is found also in West Asia and North Africa and shows clear signs of being a hybrid of NE Africa and Asia2 (so it's phylogenetic position is a blend of its parents')
  • Hp Asia2 is from South Asia
  • Hp East Asia and Hp Sahul (Australasia) need no further explanation

My main contempt is the insistence on unrealistic molecular-clock-o-logic age estimates, which are clearly miscalibrated because the migration out of Africa took place some 90-80 thousand years ago at the latest and not 55 Ka ago as they suggest with basis. Otherwise the pattern of flows must be as they described... but add at least 50% to all age mis-estimates to make sense:


It is interesting that no exogenous lineage from Neanderthals nor Erectus/Denisovans have been identified. Did we have sex but shared no saliva? Hmmm...

7 comments:

  1. I love these studies where evidence from ancient human migrations come from non-conventional markers. I don't see Australians nor Amerinds anywhere, did they forget to sample them, or maybe they don't get infected by that bacteria?

    ReplyDelete
    Replies
    1. Hp Sahul is from Australasia. Sahul or Sahulland is an alternative name for the Ice Age Australian continent, including New Guinea. I do not think they sampled Amerindians.

      Delete
  2. I might have confused Sahul with Sahel... it's the first time I hear that name applied to Australia (I have to study some geography, it will not hurt me).

    "It is interesting that no exogenous lineage from Neanderthals nor Erectus/Denisovans have been identified. Did we have sex but shared no saliva? Hmmm... "

    There isn't any evidence that west Africans carry a significant amount of Eurasian ancestry, either.

    ReplyDelete
    Replies
    1. The name Sahul is taken from the Sahul banks or shoal, a low laying sea area between Australia and New Guinea that was emerged in the Ice Age. As of late I prefer to use Australasia, although admittedly some smaller portions like New Zealand were not colonized until much later.

      "There isn't any evidence that west Africans carry a significant amount of Eurasian ancestry, either".

      Nah. Of what Dienekes says: half of half of half... and it's still too much.

      Delete
  3. "it's the first time I hear that name applied to Australia"

    Technically 'Sahul' and 'Australasia' are not synonymous. Sahul is the region conected during periods of lowered sea level: Australia and New Guinea. Australasia often includes regions beyond that continental region such as New Zealand:

    http://en.wikipedia.org/wiki/Australasia

    Quote:

    "Australasia is a region of Oceania comprising Australia, New Zealand, the island of New Guinea, and neighbouring islands in the Pacific Ocean".

    "There isn't any evidence that west Africans carry a significant amount of Eurasian ancestry, either".

    That is a further example of why the results do not convey the full story.

    "Hp East Asia and Hp Sahul (Australasia) need no further explanation"

    I wouldn't place too much weight on the conclusions concerning Hp Sahul. The paper really only concerns African and European populations and the only reference to Sahul is an ealier paper by some of the same authors:

    http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&cmd=Search&doptcmdl=Citation&defaultField=Title%20Word&term=Moodley%5Bauthor%5D%20AND%20The%20peopling%20of%20the%20Pacific%20from%20a%20bacterial%20perspective.

    Map from the article:

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2827536/figure/F2/

    Here we see that the bacterium looks to have moved east from Australia/New Guinea. Obviously more work needs to be done in the region.

    ReplyDelete
    Replies
    1. "That is a further example of why the results do not convey the full story".

      There is no evidence of any major Eurasian ancestry in West Africans. Dienekes just imagines things.

      Delete
  4. Now Otzi shares his H pylori sample with us. Thanks, Otzi.

    ReplyDelete

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