Scientists find some microbes in Ötzi the Iceman mummy are still alive

Scientists are looking at Ötzi the Iceman, the well-preserved mummy of a man who died about 5,300 years ago, and who has been widely studied, as a "dynamic ecosystem" of microbes, some of whose elements are still viable today, according to a new study.

In a comprehensive DNA analysis of the microbes found inside and outside Ötzi's mummified body, scientists have linked several types of fungi to the cold mountain environment where he died. It is likely that these fungi colonized his body and then froze with it. Their natural resistance to cold has allowed them to remain dormant while retaining their ability to live and become active even after thousands of years, according to a study published in the journal Microbiome last week.

In fact, researchers reported that some of these microbes are "not just dormant remnants," but are slowly multiplying, possibly within microscopic pockets of moisture in the mummy. This suggests that the ability of microbes to survive and remain active within ancient remains may be greater than previously thought, which should be taken into account when preserving and handling these remains.

Anders Bergström, a researcher in evolutionary genomics at the University of East Anglia, told CNN: "In many studies dealing with DNA extracted from ancient human remains, microbial DNA is largely ignored, and it is often unclear whether it is as old as the body or the result of more recent contamination."

Bergström, who was not involved in the new study, added: "This particular study of Ötzi offers interesting insights into this matter."

Scientists assumed that Ötzi the Iceman was not accompanied by any humans when he breathed his last in the cold Ötztal Alps, but he was not entirely alone. Trillions of microbes lived inside his body and continued to do so after his death, including species that came from the site where he died.

Frank Maixner, the lead author of the study and head of the Institute for Mummy Studies at Eurac Research, where the research on the mummy was conducted, said: "These microbes give us a unique and valuable glimpse into what the gut microbiome of humans in the Copper Age was like, before the Industrial Revolution reshaped the human microbiome."

Maixner told CNN: "We identified ancient intestinal bacteria preserved inside Ötzi, which are very rare in people living modern industrial lifestyles today, but are still present in some communities that follow traditional, non-industrial lifestyles."

For scientists, Ötzi's microbes are almost as interesting as Ötzi himself, as they provide evidence of his microbiome and health, and reveal aspects of the diversity of microbial communities in ancient environments.

However, microbes can also pose a challenge when it comes to preserving organic remains. Over thousands of years, ice and freezing temperatures helped protect Ötzi's body and its microbes from decomposition and decay. After the mummy was found by two hikers in 1991, on the border between Austria and Italy, it was moved to the South Tyrol Museum of Archaeology in Bolzano, where it has been kept at approximately 6 degrees Celsius below zero and 99% relative humidity, conditions similar to those found inside the glacier.

However, scientists have recently questioned whether this strategy is truly effective in curbing microbial activity, as some species are known for their ability to thrive in extremely cold environments. In addition, handling the mummy may expose it to contamination by modern bacteria and fungi, making it more difficult to accurately determine the original microbial composition.

Managing Microbes

In the new study, scientists conducted a detailed survey of the microbes associated with Ötzi. They examined the water reservoirs within his body, took swabs from the mummy's surface, and collected samples of exposed internal tissues. They also studied soil taken from beneath the mummy during its excavation in 1991, and used data from samples previously collected from Ötzi's deep intestines.

The researchers also collected airborne microbes from the mummy's preservation chamber and the room where handling of the remains takes place, and then attempted to culture some of them in the laboratory. After extracting DNA from live and non-live samples and examining the degree of their degradation, they were able to identify the types of bacteria and fungi and estimate whether they were ancient or modern. This helped them distinguish between the original microbes associated with Ötzi, those that transferred to his body after death, and others that may have been introduced later during preservation and study processes.

According to the study, the most common microbes on Ötzi's surface tissues were bacteria "Methylobacterium" and "Sphingomonas," which are likely to have been transferred to him as a result of modern human handling. Researchers also attributed another type of bacteria, "Staphylococcus," to the mummy's microbiome.

The researchers found four types of yeasts on and inside Ötzi's body:

Glaciozyma,

Goffiomyces,

Marakiya,

and Phenoliferia.

Genetic similarities between them and cold-adapted fungi found in places like Antarctica indicated that they were environmental microbes, while significant damage to their DNA linked them to the ancient Alpine ecosystem where Ötzi lived.

Frank Maixner said: "Our findings provide a basis for future microbial surveys of the Iceman." He added that knowing the types of microbes present will help researchers understand the role of these fungi and bacteria and how they interact within the "ecosystem" that Ötzi's body forms.

One type of yeast, Glaciozyma, showed a greater abundance on the mummy compared to 2010, with less damage to its DNA, suggesting that it may still be capable of multiplying despite the freezing conditions in the museum. All yeast types, except Marakiya, also possessed genes that allow them to feed on compounds previously used to preserve ancient remains, as well as organic matter. Although no signs of decay were observed on the mummy, this discovery raises concerns about its integrity and future preservation methods.

René Serecitos, a research professor at the National Autonomous University of Mexico, who was not involved in the study, described it as "excellent work that combines several research methods," including two types of gene sequencing techniques that provided detailed data on fungi and bacteria.

He told CNN: "The analysis I find most interesting is the one based on culturing microorganisms, as this method allows the recovery of organisms that may be up to 5,300 years old."

However, Serecitos pointed out that it may be too early to rule out the possibility that one of these microbes believed to have become active, the bacterium "Staphylococcus," may have reached the mummy as a result of recent contamination, as this type is common on human skin. He added that sequencing the genome of the sample and comparing it with historical and modern strains of this bacterium could help determine its true age.

In the decades since Ötzi's discovery, scientists have been able to gather many details about his life and violent death when he was about 46 years old. Studies have revealed that his last meal included grains, plants, and meat from deer and ibex.

Deep wounds on his hand and an arrow lodged in his shoulder indicate that his final days involved violence, and he likely bled to death from the shoulder injury. Ötzi carried 61 tattoos, which are among the oldest known in the world.

Calcium deposits in his heart revealed indicators of heart problems, while his intestines contained the bacterium "Helicobacter pylori," which is linked to an increased risk of stomach cancer and peptic ulcers.

These new microbial discoveries may open the door to a deeper understanding of Ötzi and other remains from the depths of the past.

Anders Bergström said: "We hope that similar detailed studies will be conducted on a wider range of human and animal remains, especially on bone tissue, which is used as the primary material in most ancient DNA research."