Frozen Ötzi yeasts still alive, slowly growing

Ötzi yeasts – Scientists studying Europe’s oldest natural mummy, Ötzi, say several cold-tolerant yeasts found on and inside him appear to still be alive and reproducing in the glacier-like conditions of his storage. Comparing samples from 2010 and 2019, they report signs of

In 1991. two mountaineers—one of them Reinhold Messner—helped bring attention to Europe’s oldest natural human mummy. Ötzi. in the Otztal Alps between Austria and Italy. Ever since. Ötzi has been kept in carefully maintained conditions. as close as possible to the glacier that preserved his body for more than 5. 000 years.

That preservation routine is exacting. His chamber is kept at a brisk -6º Celsius, with 99 percent humidity maintained by a spray of UV-treated water. The setup is meant to stop the microbes that usually help break down human remains from doing their work. And yet the researchers behind a new study say they found something they did not expect: the same environment that protects Ötzi also appears to be the perfect setting for a few microbes he carried down from the mountains.

Sarhan and colleagues, studying samples from the mummy, identified four strains of cold-tolerant yeasts. They are closely related to yeasts previously found in Arctic glaciers. in Antarctica. and high in the mountains of Italy and Russia. Unlike Ötzi’s long-dead gut bacteria—known only from broken. aging fragments of DNA—the yeasts seem to be alive and reproducing. though at what the researchers describe as a glacial pace.

“These yeasts have accompanied Ötzi on his long journey through the millennia,” said Frank Maxiner, director of the Institute for Mummy Studies at Eurac and a coauthor of the recent study, in a press release.

The yeasts were detected on Ötzi’s skin, in his stomach, and in water sampled from inside his body. Sarhan and his colleagues cultured live yeast from the samples. At the same time. their shotgun metagenomics results turned up short fragments of DNA. most showing the kind of damage that typically builds up as DNA molecules break down over time—an ancient DNA signature. Put together. that pattern suggests the yeasts most likely had been living on and in Ötzi since shortly after he died.

The researchers then looked for change over time by comparing samples taken in 2010 to those taken in 2019. They found longer fragments and less damage on average in the later samples. In other words. there appeared to be more recent DNA in the mix—evidence that the yeasts were slowly but persistently growing even under storage conditions designed to keep decay at bay.

The story is unsettling in a way that feels oddly personal: the same chamber built to keep Ötzi stable seems to have become home to a small. stubborn colony. For the scientists studying him. the question now isn’t whether microbes can survive in that world. but how long they can continue doing so—carried forward not by a chain of warm-blooded hosts. but by cold. UV-treated persistence.

Ötzi ancient microbes yeasts cold-tolerant yeasts mummy studies Eurac Institute for Mummy Studies glacial preservation ancient DNA metagenomics arctic glaciers Antarctica Italy Russia