The result was an unexpected domestication of the story: a man who had been treated as a window into a remote and alien past was also, in some measurable genomic sense, a relative of people who live in the region today. The G haplogroup signal has persisted in the Tyroleans over five millennia, even as the broader population experienced the Bronze Age steppe expansion and all the subsequent migrations, conquests, and mixings of European history.
—
## H. pylori in His Stomach: A Story of Migration
One of the more unexpected contributions of Ötzi’s ancient DNA record came from his gut microbiome rather than his own genome.
In 2016, a team analyzing DNA extracted from his stomach contents identified H. pylori bacteria — the pathogen known in modern medicine as a leading cause of gastric ulcers and a contributor to stomach cancer risk. This was not surprising in itself: H. pylori infects a large proportion of modern humans globally, and its presence in a Copper Age stomach was not unexpected.
What was surprising was which strain Ötzi carried. Modern H. pylori populations fall broadly into strains associated with African origin and strains associated with Asian origin, with the European strain representing a mixture of these two inputs. Genomic analysis of Ötzi’s H. pylori showed it was most closely related to strains now found primarily in South Asia — particularly in modern Northern Indian populations — with relatively little of the African input that characterizes most modern European H. pylori.
This finding contributed to a growing body of work suggesting that the mixing of H. pylori strains that produced the modern European population did not happen until after Ötzi’s time. The strain he carried looked like what you would find in someone whose ancestors came from Anatolia and further east, without the African admixture that entered the European population later. The Ötzi H. pylori paper proposed that this later mixing of strains was potentially associated with the Bronze Age steppe expansion — the same population movement that the 2023 genomic reanalysis confirmed had not yet reached Ötzi’s community.