What Ötzi’s stomach bacteria disclose about European migration


A Kiel research team is involved in the detection of pathogens from the glacier mummy

Scientists from EURAC sampling the Iceman

Scientists from EURAC in Bozen took samples from the Iceman which where then analysed in the Graduate School’s aDNA laboratory. © Samadelli Marco/EURAC

Ötzi the Iceman was infected with the ulcer-causing bacterium Helicobacter pylori and the colonization history of Europe is more complex than previously assumed. These seemingly unrelated findings were recently attained by an international research team led by Dr. Albert Zink and Dr. Frank Maixner of the European Academy (EURAC) in Bolzano. Junior Professor Ben Krause-Kyora and Professor Almut Nebel of the Institute of Clinical Molecular Biology (IKMB) of Kiel University were significantly involved in the achievement of the new insights. In the Ancient DNA (aDNA) Laboratory, they isolated the 5300-year-old Helicobacter pylori genome from the stomach contents of the glacier mummy and enriched it using the most current methods. The obtained aDNA sequences were subsequently decoded using high-performance equipment of the IKMB. Thereafter, scientists from Vienna, Jena and South Africa performed further analyses. The results of the research team have recently been published in the academic journal Science. The Ancient DNA Laboratory was established by the Graduate School Human Development in Landscapes with the support of the Faculty of Medicine in Kiel. Further development of the laboratory to secure highest-level, state-of-the-art aDNA analysis is planned.

“We are even more excited about the recent results as they were unexpected,” remarks Ben Krause-Kyora. “Although the gastric mucosa, in which the bacteria of today’s patients are verified, is not preserved well enough in Ötzi’s remains to permit diagnosis, we did succeed in identifying singular Helicobacter sequences within the genetic material of the entire stomach contents by using the latest enrichment and sequencing methods in order to reconstruct the complete genome of the bacteria.” In Germany, ca. 33 million people are currently infected with Helicobacter pylori, of which less than 10% develop gastritis, ulcers or similar symptoms during the course of their lifetime. “It is quite conceivable that Ötzi suffered from such a disorder, the conditions were certainly given”, asserts Almut Nebel with regard to one of the research results. However, due to the poor preservation of the gastric mucosa such an illness cannot be confirmed.

Nevertheless, the verified bacteria enable insights that reach far beyond Ötzi’s medical history. “Since tens of thousands of years, humans carry Helicobacter pylori germs that exhibit regional differences and are usually passed from mother to child”, explains Almut Nebel. Today’s Europeans carry a Helicobacter strain, which formed – according to previous findings –more than 10.000 years ago in the Middle East through the intermixing of an African with an Asian strain of the bacteria. “Until now, it has been assumed that this Helicobacter strain spread out across Europe during the course of Neolithic migration long before Ötzi’s death”, describes Nebel. “We assumed, therefore, that Ötzi also carried this bacterial strain.” But as Thomas Rattei, population geneticist of the University of Vienna, and colleagues from South Africa, Germany and the USA analysed the Helicobacter genome identified in Kiel, the surprising result was a bacterial strain that is primarily found today in Central and South Asia. Almut Nebel und Ben Krause-Kyora agree on the interpretation of the results: “The colonization of Europe proceeded in a much more complex manner than previously assumed, because the Neolithic farmers from the region of the “Fertile Crescent” were apparently not the carriers that brought the European Helicobacter strain with them. This consequently formed much later than previously thought and must have arrived here through different channels.”

Almut Nebel and Ben Krause-Kyora are members of the Graduate School Human Development in Landscapes (GSHDL) and of the Cluster of Excellence Inflammation at Interfaces, which financially supported the analysis of Ötzi’s stomach contents.

Original publication: Frank Maixner, Ben Krause-Kyora, Dmitrij Turaev, Alexander Herbig, Michael R. Hoopmann, Janice L. Hallows, Ulrike Kusebauch, Eduard Egarter Vigl, Peter Malfertheiner, Francis Megraud, Niall O´Sullivan, Giovanna Cipollini, Valentina Coia, Marco Samadelli, Lars Engstrand, Bodo Linz, Robert L. Moritz, Rudolf Grimm, Johannes Krause, Almut Nebel, Yoshan Moodley, Thomas Rattei, Albert Zink (2016): The 5,300-year-old Helicobacter pylori genome of the Iceman. Science

Link to the original publication’s abstract in Science: www.sciencemag.org/lookup/doi/10.1126/science.aad2545