Helicobacter pylori from Peruvian amerindians: traces of human migrations in strains from remote Amazon, and genome sequence of an Amerind strain.
BACKGROUND
The gastric pathogen Helicobacter pylori is extraordinary in its genetic diversity, the differences between strains from well-separated human populations, and the range of diseases that infection promotes.


RESULTS
Housekeeping gene sequences from H. pylori from residents of an Amerindian village in the Peruvian Amazon, Shimaa, were related to, but not intermingled with, those from Asia. This suggests descent of Shimaa strains from H. pylori that had infected the people who migrated from Asia into The Americas some 15,000+ years ago. In contrast, European type sequences predominated in strains from Amerindian Lima shantytown residents, but with some 12% Amerindian or East Asian-like admixture, which indicates displacement of ancestral purely Amerindian strains by those of hybrid or European ancestry. The genome of one Shimaa village strain, Shi470, was sequenced completely. Its SNP pattern was more Asian- than European-like genome-wide, indicating a purely Amerind ancestry. Among its unusual features were two cagA virulence genes, each distinct from those known from elsewhere; and a novel allele of gene hp0519, whose encoded protein is postulated to interact with host tissue. More generally, however, the Shi470 genome is similar in gene content and organization to those of strains from industrialized countries.


CONCLUSIONS
Our data indicate that Shimaa village H. pylori descend from Asian strains brought to The Americas many millennia ago; and that Amerind strains are less fit than, and were substantially displaced by, hybrid or European strains in less isolated communities. Genome comparisons of H. pylori from Amerindian and other communities should help elucidate evolutionary forces that have shaped pathogen populations in The Americas and worldwide.
Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA.
Dangeruta
D
Kersulyte
Awdhesh
A
Kalia
Robert H
RH
Gilman
Melissa
M
Mendez
Phabiola
P
Herrera
Lilia
L
Cabrera
Billie
B
Velapatiño
Jacqueline
J
Balqui
Freddy
F
Paredes Puente de la Vega
Carlos A
CA
Rodriguez Ulloa
Jaime
J
Cok
Catherine C
CC
Hooper
Giedrius
G
Dailide
Sravya
S
Tamma
Douglas E
DE
Berg
D000569:Americas; D000595:Amino Acid Sequence; D001208:Asia; D001426:Bacterial Proteins / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004641:Emigration and Immigration; D005060:Europe; D014644:Genetic Variation; D016680:Genome, Bacterial / Q000235:genetics*; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007199:Indians, South American; D008969:Molecular Sequence Data; D010568:Peru; D010802:Phylogeny; D011157:Population Dynamics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013997:Time Factors
D001426:Bacterial Proteins; D004269:DNA, Bacterial