Modern stress got you down? Otzi the iceman had it worse
We already knew famous frozen mummy found in Alps had long list of ailments. Turns out he might also have been dealing with ulcers
Poor Otzi lived and died painfully. The 5,300-year-old “Iceman,” whose frozen remains were discovered by hikers in the Italian Alps, has been diagnosed by modern-day scientists with arthritis, spinal damage, tooth decay, lactose intolerance, and a murderous arrow wound to the shoulder that cut an artery, killing him.
Now European scientists have extracted Helicobacter pylori, the bacterium that causes ulcers, from the ice mummy’s stomach.
While they can’t say for sure that Otzi was in gastric distress — his stomach lining was too decayed to examine — they did discover that he carried a virulent strain of the bug, and that his stomach contained proteins associated with inflammatory immune response.
“It was for sure a tough life,” said Albert Zink of the Institute for Mummies and the Iceman at the European Academy of Bozen/Bolzano and a co-author of a paper describing the findings in the journal Science this week.
Fascinatingly, the researchers have used Otzi’s stomach bug to fill in blank spots in the bacterial history of Europe. Because H. pylori is an incredibly successful human pathogen — approximately half the world’s population are carriers, though only a fraction will experience ulcers — researchers have used geographically distinct bacterial strains to reconstruct human migrations.
Otzi’s H. pylori is the oldest specimen ever sequenced, and his strain is very different than that of modern Europeans.
“It’s a very cool thing to do, to get it from the Iceman,” said Daniel Falush, a statistical geneticist at the U.K.’s Swansea University.
“They made a clear scientific finding about what he had, which is definitely new.”
Scientists believe that the first anatomically modern humans to disperse out of Africa were already carrying H. pylori, and have discovered that different strains can be associated with different human populations. In the far north of India, H. pylori from the stomachs of Buddhists is genetically distinct from H. pylori from the stomachs of Muslims, one study found.
In Europe, a continent with a complicated history of migration, the dominant H. pylori is a hybrid of two strains, one that probably evolved in Central Asia and another in Northeast Africa.
But scientists have not been able to deduce when or how these two strains began to commingle.
Otzi’s H. pylori, the researchers write in Science, is a nearly pure Asian strain. Genetically, it is most closely related to an H. pylori strain now found primarily in India. Otzi’s bacterium had almost nothing of the African admixture common in present-day European stomachs. That does not mean Otzi came from India: isotope analysis has shown that he lived his whole life in the Alps. What it does suggest is that the influx of Northeast African H. pylori came to Europe some time after Otzi died.
Researchers argue about how tightly bound the link between human migrations and H. pylori strains really is, and the Science co-authors acknowledge that the conclusions that can be drawn here, especially from a single specimen, are limited. Perhaps the influx of African H. pylori was brought to Europe in the last 5,000 years by waves of migrants from the Middle East or from the Fertile Crescent — we can’t really say for sure. The scientists would like to sample pathogens from the stomachs of other ancient mummies.
“Something really dramatic has happened in the last 5,000 years in H. pylori DNA that hasn’t happened in human DNA. There will be an interesting reason for that . . . We haven’t figured it all out yet,” said Falush.