The early migrations of humans to America from Siberia, which took place about 12,000 years ago, were tracked using the bacteria they carried.
Experts examined samples of the gastric bacterium Helicobacter pylori, which is associated with human activity. Analyzes using new statistical methods provide evidence that humans colonized America as a result of the migration of evolutionarily ancient northern Eurasians across the Bering Bridge.
Early research discovered three populations of the H. pylori bacterium in individuals in Eurasia and America. The data also indicated that one of these bacterial populations, including Native American H. pylori, was common throughout Siberia. It is assumed that this population came with people to America.
H. pylori is a stomach bacterium that infects about half of people worldwide, but scientists have found that its genetic sequence also varies depending on the region in which it is identified.
In order to reconstruct the history of human movement, the authors compared evolutionary models and time intervals using a technique called approximate Bayesian computation (ABC).
The results showed that a tiny population of H. pylori colonized America in a single migratory event approximately 12,000 years ago.