Identification of New Subpopulations in Native Americans and Mestizos From Peru.

Region-specific subpopulations have been identified. It is proposed that the hspAmerind subpopulation is being displaced from the Americans by an hpEurope population following the conquest. Our study aimed to describe the genomes and methylomes of isolates from distinct Peruvian communities: 23 strains collected from three groups of Native Americans (Asháninkas [ASHA, = 9], Shimaas [SHIM, = 5] from Amazonas, and Punos from the Andean highlands [PUNO, = 9]) and 9 modern mestizos from Lima (LIM).

Socioeconomic and nutritional factors account for the association of gastric cancer with Amerindian ancestry in a Latin American admixed population.

Gastric cancer is one of the most lethal types of cancer and its incidence varies worldwide, with the Andean region of South America showing high incidence rates. We evaluated the genetic structure of the population from Lima (Peru) and performed a case-control genetic association study to test the contribution of African, European, or Native American ancestry to risk for gastric cancer, controlling for the effect of non-genetic factors. A wide set of socioeconomic, dietary, and clinic information was collected for each participant in the study and ancestry was estimated based on 103 ancestry informative markers.

Attenuated CagA oncoprotein in Helicobacter pylori from Amerindians in Peruvian Amazon.

Population genetic analyses of bacterial genes whose products interact with host tissues can give new understanding of infection and disease processes. Here we show that strains of the genetically diverse gastric pathogen Helicobacter pylori from Amerindians from the remote Peruvian Amazon contain novel alleles of cagA, a major virulence gene, and reveal distinctive properties of their encoded CagA proteins. CagA is injected into the gastric epithelium where it hijacks pleiotropic signaling pathways, helps Hp exploit its special gastric mucosal niche, and affects the risk that infection will result in overt gastroduodenal diseases including gastric cancer.

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.

Principal Findings: 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.