Million-Year-Old Mammoth Tooth Carries Oldest Host-Associated Bacteria DNA Ever Found

Bacteria, the oldest life on earth, evolved approximately 4 billion years ago, the first fossilized traces dating from 3.5 billion years to 3.7 billion years. But fossils alone only indicate the past. To really understand longtime organizations, scientists need their genetic plan.

DNA, however, is fragile. Due to his chemical instability, he cannot resist the test of time. Thanks to the progress of sequencing technology and exceptionally preserved remains, researchers now postpone the limits of the measure to which genetic data can reach.

In a new study, scientists at the University of Stockholm and the Swedish Museum of Natural History have recovered the oldest bacterial DNA associated with the host never found, extract from Mammoth teeth more than 1.1 million years. Published in CellResearch highlights possible pathogens linked to microbes causing disease in elephants, modern cousins ​​of mammoths.

“This work opens a new chapter in understanding the biology of extinct species. Not only can we study the genomes of the mammoths themselves, but we can now start to explore the microbial communities that lived inside, “said LOVE DALEN, professor of evolutionary genomics at the Palaeogenetic Center for a press statement.

Understand ancient microbes

Usually, most of the knowledge of ancient microbes come from preserved DNA in places such as permafrost, amber, salt crystals and high -high sediments, or human remains and artefacts. Because DNA quickly disintegrates, older samples rarely give results.

Studies on the human microbe dominate research on ancient DNA, in part because these remains are younger and easier to work. The oldest DNA to date – about 2 million years – has been found in frozen soil in Greenland, offering an overview of an ecosystem valued for a long time.

Mammoth’s new analysis goes further. By recovering bacterial sequences from woolly mammoth and steppe, including one over 1.1 million years, the team has set a new record for microbial DNA associated with the host.

Learn more: A lyophilized woolly mammoth gives chromosomes of 52,000

Bacterial strains identified from mammoth samples

After screening and filtration of DNA of 483 mammoth samples, they identified 310 microbes linked to mammoth tissues. Most were environmental or post mortem colonizers, but six clades stood out as real bacteria associated with the host, including Actinobacillus, Pasteurella, Streptococcus, And Erysipothrixsome of which could have been pathogenic.

According to the press release, one of the bacterial strains identified is closely linked to a bacteria which still causes fatal epidemics in African elephants. Elephants are living parents closest to mammoths, therefore, the results raise the possibility that mammoths are faced with similar infections.

More striking, the researchers have rebuilt the partial genomes of Erysipothrix Originally from a 1.1 million 1.1 million mammoth sample, microbial DNA associated with the host was recovered.

“Our results repel the study of microbial DNA beyond a million years, opening up new possibilities to explore how the microbes associated with the host have evolved in parallel with their hosts,” said Benjamin Guinet, the main author of the study.

Microbes that remained with mammoths for a long time

“As microbes evolve quickly, obtaining reliable DNA data over more than a million years was like following a path that continued to rewrite. Our results show that ancient remains can preserve biological information far beyond the host genome, offering us perspectives on how microbes have influenced the adaptation, illness and extinction of Pleistocene ecosystems, “explained the main author Tom Van Valk in the Declaration.

Although it is difficult to say how exactly these microbes affected gigantic health, the study offers an unprecedented overview of the microbiomas of the extinguished megafauna. The results indicate that certain microbial lines lived alongside mammoths for large stretches of time, persisting in different regions and evolutionary stages.

By showing that animal microbiomas even of a million people can be recovered, the study opens up new paths to explore how microbes shaped the life and death of ancient species.

Learn more: Why the pygmy mammoth was just 5 feet high

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