Were Otzi the Iceman’s ancestors from Asian?

Analysis of microbes extracted from inside of Otzi, a 5,300-year-old mummy, has unveiled not only that the frozen Copper Age mummy died from a stomach bug, but also provided new information about ancient human migration.

“We had assumed that we would find the same strain of Helicobacter in Oetzi as is found in Europeans today”, said Thomas Rattei, from the University of Vienna, in Austria, who worked on the study.

By examining the DNA, scientists were able show through the type of DNA sequence present and the degradation of the DNA that the bacteria was from the Iceman and not some other form of contaminant. Therefore Frank Maixner and colleagues took biopsy samples to look for this pathogen, which is estimated to occur in up to 50% of people in low-income settings. His immune system had clearly reacted to the bacteria; the researchers found traces of marker proteins that usually represent an inflammatory response to infection.

The analysis of the Iceman’s stomach showed the presence of Helicobacter pylori that’s somewhat different from the strain found in modern Europeans. However, the researchers found that H. pylori from the Iceman is very similar to the strains from Northern India and Southern Asia, suggesting that the early human migration from Africa arrived in Europe only within the past few thousand years. Because scientists realized that the contents of the Iceman’s stomach were still intact.

“One of the first challenges was then to obtain samples from the stomach without doing any damage to the mummy”, said Albert Zink, senior author on the study and head of the Institute for Mummies and the Iceman.

H. pylori strains are known to mix and recombine into hybrids when they come into close contact for a significant period of time: When couples pair up, when children play together, and so on. The long-dead man’s clothing, tools, manner of death, and even tattoos have given us a peek at how life was 5,300 years ago – or how it was for Otzi, anyway. But getting to this point in their research wasn’t easy; scientists only noticed that the mummy contained a full stomach in 2010, after re-examining CT scans of the body.

“In people who have it, it’s the dominate organism in their stomach”, he says. The new strain may have evolved in the Middle East and then been introduced by later waves of farmers migrating out of the Fertile Crescent.

For now, researchers are primarily celebrating a unique snapshot of the microbial life inside one famous – and somewhat unfortunate – mummy from ancient Europe. As researchers continue to study Otzi, it’s likely they’ll uncover more about ancient and modern humans.

“He had several heel drop fractures, degenerate rate of arthritis, vascular calcification and the presence of an arrowhead in his left shoulder was detected”, said Zink.

“One thing we definitely want to do is to extend our investigation also to other mummies, because we could show how it works and that we are able to reconstruct H. pylori from stomach material”, said study co-author Albert Zink, a paleopathologist from the European Academy of Bozen/Bolzano in Italy. “I would see, actually, a totally new research area, which I would call paleomicrobiology, that studies particularly ancient microbes”.