Ötzis 5.300 Jahre altes Mikrobiom metabolisiert und entwickelt sich immer noch

Ötzi the Iceman was murdered with an arrow 5,300 years ago, but his gut microbes never got the memo. A new study in Microbiome shows that yeast strains from his digestive tract are still metabolically active—and some have adapted to the very freezer meant to preserve him.

Mohamed Sarhan, a microbiologist at Italy’s Eurac Research Institute for Mummy Studies, led the team that analyzed microbial and fungal populations from Ötzi’s skin, tissues, and thawed water collected inside the mummy. They found multiple species of anaerobic bacteria including Romboutsia hominis, Clostridium moniliforme, and Ruminococcus bromii—the same kinds of bacteria that helped Ötzi digest his high-fat, dried-meat-and-fern diet 5,300 years ago.

Yeasts Are Still Working After 5,300 Years

Some of those bacteria have become rare in modern guts, but they’re still present in Ötzi. Sarhan notes that two or three species found in the Iceman have never been reported in other ancient mummies and are "very rarely found in modern humans" except in some nonindustrialized societies.

More surprising: yeast samples taken from Ötzi’s skin, stomach, and meltwater revealed cold-adapted species that likely originated in the alpine environment where he died. When the team compared those samples to ones collected nine years earlier, they found the yeast populations had shifted. Species able to digest phenol—the chemical used to disinfect the Iceman—have grown despite the constant −6°C (21.2°F) storage.

Phenol-Eating Microbes Complicate Preservation

That finding matters for Ötzi’s caretakers. "The main motivation of this study was the microbiological conservation of the mummy," Sarhan says. The phenol-digesting yeasts show that current preservation conditions aren’t static—microbes are evolving in response to the very protocols meant to stop decay.

Sarhan warns that conservation must account for everything: the body, biomolecules, proteins, DNA, metabolites, and internal bacteria. If those microbes keep shifting, they could degrade the very genetic material researchers hope to study.

What This Means for Frozen Bioarchives

Ötzi’s microbiome is a snapshot of a Stone Age gut, but it’s also a living laboratory. The same cold-adapted yeasts that survived millennia in a glacier are now adapting to a modern freezer. That knowledge could help museums and biobanks improve how they preserve other frozen discoveries—whether ancient mummies or permafrost samples.

Sarhan expects more discoveries as sequencing technology improves. The mystery of how exactly Ötzi died may stay cold, but his microbiome is anything but frozen in time.

Source: Ötzi the murdered Iceman's microbiome is still active
Domain: scientificamerican.com