An African origin for the intimate association between humans and Helicobacter pylori

Nature 445:915-8, 2007

Speaker: 洪惠雯                                                   Date: 2007 /4/11

Commentator: 孫孝芳  教授                           Time:13:10~14:00  Room:601

Abstract:

Helicobacter pylori, as a definite carcinogen of gastric cancer and cause chronic gastritis. Infection with H. pylori occurs worldwide. In this report, the authors used a data set of 769 H. pylori isolates from 51 ethnic sources to test whether patterns in their geographic distribution imitate human beings. There are 3850 nucleotides were sequenced for each isolates, 1418 were polymorphic and used to define bacteria populations. The program STRUCTURE was implemented to deduce and reconstruct ancestral population models. Analysis of the global H. pylori samples identified seven ancestral populations, hpAfrica1, hpAfrica2, hpEastAsia, hpEurope1, hpEurope2, hpAsia2 and hpNEAfrica. Therefore, it implied that genetic diversity within modern humans decreases with distance from east Africa. Furthermore,  the genetic simulations with human and H. pylori data indicated that H. pylori and humans spread from east Africa about 58000 years ago. The genetic diversity of H. pylori seems to be a mirror of its human host. In conclusion, H. pylori and human populations have been evolving intimately ever since, with range-limited transmission by horizontal infections.

Reference:

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