Helicobacter pylori (H. pylori) is a pathogen commonly found residing in the human stomach. It is found in fifty percent of the world’s population, but only ten percent of carriers develop any symptoms. Symptoms of infection include gastritis and gastric ulcers. In extreme cases, gastric carcinomas may develop. There are various strains of H. pylori associated with humans and they can undergo recombination to produce new strains. Different strains of H. pylori are associated with different geographic areas such Asia, Africa, and Europe.
Scientists speculate that H. pylori has been associated with humans for at least one-hundred thousand years, which has allowed scientists to study migration patterns of humans by tracing the distribution of the various strains. Researchers screened biopsies taken from the gastrointestinal tract of a 5300-year-old mummy from the Copper Age, Otzi (also known as Iceman). The remarkably well persevered mummy was found two and a half decades ago in the Alps near the Austrian-Italian border. The study utilized a combination of polymerase chain reaction (PCR) and metagenomics analyses to identify the presence and the genetic profile of H. pylori.
The lead investigators of the study expected that the genetic profile of Iceman to be would be similar to the modern European strains containing H. pylori. The Iceman was genetically similar to early European farmers and for this reason it was expected that the H. pylori strain he harbored would resemble that of modern Europeans. It is known that the European strain of H. pylori is derived from the recombination of Asian and African strains. However, sequence analysis of H. pylori from Iceman revealed the H. pylori strain to be similar to Asian strains than that of modern European ones. It is currently unknown during which period the hybridization even took place that gave rise to European strain of H. pylori. These findings suggest that there were other migration events that took place after the time of the Iceman.
The settlement history of Europe is complex, but these findings suggest that an Asian population must have settled in Europe before the arrival of African population, potentially revealing more about early migration patterns of humans.
Cover photo: (c) S
1. Maixner F, Krause-Kyora B, Turaev D, et al. The 5300-year-old Helicobacter pylori genome of the