Two climbers (one of them Reinhold Messner) with Ötzi, Europe’s oldest natural human mummy, in the Ötztal Alps between Austria and Italy in September 1991.
Credit: Paul Haney/Gamma-Rapho/Getty Images
Two climbers (one of them Reinhold Messner) with Ötzi, Europe’s oldest natural human mummy, in the Ötztal Alps between Austria and Italy in September 1991.
Credit: Paul Haney/Gamma-Rapho/Getty Images
Ötzi has been carefully preserved, kept as close as possible to the glacier that has preserved his body for more than 5,000 years. The chamber temperature is -6º Celsius, with 99 percent humidity carefully maintained by UV-treated water spray. This is enough to protect the mummy from most of the microbes that normally help decompose human remains. But Sirhan and his colleagues were surprised to find that it was also an ideal environment for some of the microbes that Ötzi had brought down from the mountains with him.
In the mummy samples, Sirhan and his colleagues found four strains of cold-tolerant yeast, all closely related to similar yeasts found in Arctic glaciers, Antarctica, and the mountains of Italy and Russia. And unlike Ötzi’s long-dead gut bacteria, which left behind broken, old fragments of DNA, the yeast appear to be alive and reproducing (albeit, ahem, at a glacial pace).
“These yeasts have accompanied Ötzi on his long journey through the millennium,” Frank Meissner, director of the Institute for Mummy Studies in Iraq and co-author of the recent study, said in a press release. (Otzi probably doesn’t find it very comfortable, but you never know.)
Molten ancient germs or long-lived colonies?
species of yeast Phenolifera, glaciozyma, gofouzimaAnd marciaFor mycology fans – water samples were taken from Ötzi’s skin, his stomach and inside his body. Sirhan and his colleagues cultured live yeast from the samples, but their shotgun metagenomics results also revealed a host of smaller fragments of DNA, most of which bear the kind of damage that occurs when DNA molecules break over time. This is a detection of ancient DNA, which means the yeasts were likely living in Ötzi’s body shortly after his death.
And when Sirhan and his colleagues compared samples taken in 2010 to samples taken in 2019, they saw longer fragments and less damage on average — in other words, there was more recent DNA in the mix, which showed that the yeasts were growing slowly but steadily.
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