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Guide to Patagonia's Monsters & Mysterious beings

I have written a book on this intriguing subject which has just been published.
In this blog I will post excerpts and other interesting texts on this fascinating subject.

Austin Whittall


Friday, January 8, 2016

Helicobacter pylori and the Out of Africa theory


A paper published in Science (F. Maixner, 2016 [1]) reported that they studied the DNA of the Helicobacter pylori recovered from Ötzi, the iceman, whose mummified body was discovered in an Alpine glacier melt in 1991. They body is 5,300 years old and they expected to find the typical European variety of H. pylori in the remains of his stomach. Instead they found the Asian variety. Casting a shadow on the current Out of Africa theory of the peopling of Europe.


Their abstract says: (bold is mine) "The stomach bacterium Helicobacter pylori is one of the most prevalent human pathogens. It has dispersed globally with its human host, resulting in a distinct phylogeographic pattern that can be used to reconstruct both recent and ancient human migrations. The extant European population of H. pylori is known to be a hybrid between Asian and African bacteria, but there exist different hypotheses about when and where the hybridization took place, reflecting the complex demographic history of Europeans. Here, we present a 5300-year-old H. pylori genome from a European Copper Age glacier mummy. The “Iceman” H. pylori is a nearly pure representative of the bacterial population of Asian origin that existed in Europe before hybridization, suggesting that the African population arrived in Europe within the past few thousand years."


I wrote about this some time ago, that the different H. pylori variants are not necessary of an African origin. These findinngs by Maixner and his team seem to support this idea.


According to the paper (it is free access), the Iceman's variant of H.pylori is closer to the South Asian one! (India, Malaysia, Bangladesh, Thailand, Philippines) and is furthest from the N.E. Africa and W. Africa variant (from Nigeria to Ethiopia)... See this graph with the different variants and Ötzi's position closest to Asian types.


So this is no man from the steppes or a Middle Eastern H. pylori variant. This copper age man has a H. pylori found in SE Asia. The route taken by humans out of Africa, and long before them, by Homo erectus to... South East Asia. Are we seeing some signal of an old variant of H. pylori here? One that predates European H. pylori and also the African one?


What is odd is that a paper by A. Keller et al., (2012) [2] found the Iceman was closely related to the population of the two islands of Corsica and Sardinia in the NW Mediterranean Sea: "Sequence analysis showed genetic distance from modern mainland European populations, but proximity to the extant populations of Sardinia. Interestingly, the Iceman's Y-haplogroup G2a4 has hitherto only been found at appreciable frequencies in Mediterranean islands of the Tyrrhenian Sea (Sardinia and Corsica). Although admixture and demographic history cannot be reconstructed from one individual alone, the Iceman's Y-chromosomal data document the presence of haplogroup G in Italy by the end of the Neolithic and lends further support to the demic diffusion model. The affinity of the Iceman's genome to modern Sardinian groups may reflect relatively recent common ancestry between the ancient Sardinian and Alpine populations, possibly due to the diffusion of Neolithic peoples." [2]


What do Sardinians and South Asians have in Common? Perhaps Keller et al. are right and it just reflects a group that survived from the days of Ötzi in isolation in those two islands, and ths same DNA is found at very low levels (less than 1%) across Europe.


The paper states that: "Furthermore, our co-ancestry results indicate that the Iceman’s strain belonged to a prehistoric European branch of hpAsia2 that is different from the modern hpAsia2 population from northern India" [1]. Which is very interesting. It is a really ancestral branch. (Neanderthal ?)


Figure 4 in the paper shows the tree, with two big branches, one is N.E.Asia and America, the other has Africa, Europe, South Asia and Oceania. That is indeed striking.


The First branch, splits into Africa and Europe, and another which holds the Iceman and also includes to India, Papua New Guinea and Sahul.


The other main branch with N. E. Asians (Korea, China and Japan) also hash the Amerindians (Peru: Puno and Cuzco variants and Venezuela) with many smaller branches. Does that imply a longer time for their diversification vs. the other human groups?


The best part is that over the last few months a series of discoveries have cast some doubt on the Out Of Africa theory: Neanderthal backflow into Africa, and the 80- 120 kya old teeth found in China. What new findings will 2016 bring with it?


Source


[1] Frank Maixner, et al., 8 January 2016: The 5300-year-old Helicobacter pylori genome of the Iceman Vol. 351 no. 6269 pp. 162-165 DOI: 10.1126/science.aad2545
[2] A Keller et al. (2012) New insights into the Tyrolean Iceman's origin and phenotype as inferred by whole-genome sequencing, Nature Communications 3, Article number: 698 doi:10.1038/ncomms1701



Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2016 by Austin Whittall © 

1 comment:

  1. "The other main branch with N. E. Asians (Korea, China and Japan) also hash the Amerindians (Peru: Puno and Cuzco variants and Venezuela) with many smaller branches. Does that imply a longer time for their diversification vs. the other human groups?"

    Judging by the fact that this East Asian-Amerindian branch has a restricted, "northern," geographic distribution in Asia, I wonder if these East Asian variants are product of a relatively recent (as in 12,000 years ago) back migration from the Americas. So prior to 12,000 years this branch could have been entirely isolated in the Americas and it's the Papuan and West Eurasian branches that were dominating Asia.

    ReplyDelete

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