The oldest genetic data ever found

Danish and British scientists claim to have extracted genetic information from a rhinoceros tooth aged 1.7 million years, making it the largest and oldest genetic data ever recorded.

Members of the same team set the previous record in 2013 by revealing sequenced bone remains of a frozen horse for 700,000 years in permafrost Yukon, Canada.

In the new work, described in an article of the journal Nature, the researchers identified an almost complete set of proteins – a proteome – in tooth enamel from a fossil found in Dmanisi, Georgia.

The project brought together scientists from the University of Copenhagen in Denmark and St John's College of the University of Cambridge in London. Their subject was a Stephanorhinus, an extinct rhinoceros that lived in Eurasia during the Pleistocene (1.6 million to 10,000 years ago).

"For 20 years, the old DNA is used to answer questions about the evolution of extinct species, adaptation and human migration, but it has limitations," says the first author Enrico Cappellini, from the Copenhagen Globe Institute.

"For the first time, we have retrieved old genetic information that allows us to reconstruct molecular evolution well beyond the usual time of DNA preservation."

"This new analysis of old tooth enamel proteins will open an exciting new chapter in the study of molecular evolution."

Researchers say that DNA data that genetically track human evolution only cover the last 400,000 years, but the lineages that led to modern humans have diversified there are around six to seven million years, which means that there is no genetic information for more than 90% of the evolutionary population. path.

In this study, they found that the proteins contained in rhinoceros tooth enamel – the hardest material found in mammals – had lasted longer than DNA and were more genetically informative than collagen, the only other protein extracted so far from fossils dating back over a million years.

"Dental enamel is extremely abundant and incredibly durable, which is why much of the fossil record is of teeth," says Cappellini.

"We have been able to find a way to retrieve more informative and older genetic information than any other source before – they come from a plentiful source in the fossil record, so the potential for application of this approach is considerable. "

Researchers say this rearrangement of the evolutionary lineage of a single species may seem a slight adjustment, but they believe that identifying the changes in many missing mammals and humans could result in significant changes in our understanding of how the world has evolved.

"This research is a game changer that opens up many opportunities for future evolutionary studies on humans and mammals," said lead author Eske Willerslev, who was also one of the authors Main topics of the 2013 study.

"This will revolutionize the investigation methods of evolution based on molecular markers and will open a whole new field of ancient biomolecular studies."