Evolutionary History of the Helicobacter pylori Genome: Implications for Gastric Carcinogenesis - PubMed (original) (raw)

Evolutionary History of the Helicobacter pylori Genome: Implications for Gastric Carcinogenesis

Pelayo Correa et al. Gut Liver. 2012 Jan.

Abstract

The genome of the bacterium Helicobacter pylori has evolved over the millennia since its migration out of Africa along with its human host approximately 60,000 years ago. Human migrations, after thousands of years of permanent settlement in those lands, resulted in seven prototypes of genetic populations of H. pylori with distinct geographical distributions. In all continents, present day isolates of H. pylori have molecular markers that reflect population migrations. The colonization of the Americas as well as the slave trade introduced European and African strains to the New World. The relationship between H. pylori genome and gastric cancer rates is linked to the presence of the cagA gene, but the knowledge on this subject is incomplete because other genes may be involved in certain populations. A new situation for Homo sapiens is the absence of H. pylori colonization in certain, mostly affluent, populations, apparently brought about by improved home sanitation and widespread use of antibiotics during the last decades. The disappearance of H. pylori from the human microbiota may be linked to emerging epidemics of esophageal adenocarcinoma, some allergic diseases such as asthma and some autoimmune disorders.

Keywords: Gastric carcinogenesis; Genome; Helicobacter pylori.

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Conflict of interest statement

No potential conflict of interest relevant to this article was reported.

Figures

Fig. 1

Fig. 1

World map indicating human migrations (arrows) and time range in years since the migrations happened. H. pylori accompanied man during the migrations and the four major H. pylori populations (as known in 1999: Europe, Northern Asia, Southern Asia, and New Zealand) are represented by concentric circles of different colors. Light green areas indicate the locations where development of agriculture and animal breeding started, resulting in expansion of human populations (From Covacci A, et al. Science 1999;284:1328-1333, with permission).

Fig. 2

Fig. 2

Phylogeography of H. pylori. Neighbor-joining tree of 64 _cagA_+ vacA s1m1 Colombian H. pylori isolates from the high-risk (black circles) and low-risk (open circles) regions, along with 380 reference strains that were previously classified into distinct ancestral haplogroups. Branches are drawn to scale to represent evolutionary distance. The colors of the branches represent the classification of strains into distinct populations (From de Sablet T, et al. Gut 2011;60:1189-1195, with permission).

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