Scientists extract the oldest genetic information from rhinoceros tooth aged 1.7 million years

Scientists have extracted the oldest genetic information ever found on a 1.7 million year old rhinoceros tooth, using a technique described as a "game changer" that could revolutionize our understanding of the world. ;evolution.

Using mass spectrometry, scientists were able to sequence proteins and read genetic data that it was impossible to obtain beforehand with the help of DNA tests. This means that they could accurately reconstruct the evolution of more backward than ever, according to the paper published in Nature.

Researchers from the University of Copenhagen and the University of Cambridge have identified an almost complete set of proteins in the tooth enamel of extinct cells. Stephanorhinuswho lived in what is now Georgia during the Pleistocene.

Proteins are chains of building blocks made up of amino acids. Scientists use mass spectrometry to reconstruct the amino acid sequence, allowing them to understand the essential genetic information of an organism.

"We have a solution that allows us to generate information going beyond the boundaries of ancient DNA and that can be applied technically to all large mammal species," said lead researcher Enrico Cappellini of the 39, University of Copenhagen. L & # 39; s independent.

"For 20 years, ancient DNA is used to answer questions about the evolution of extinct species, adaptation and human migration, but it has limitations. Now, for the first time, we have retrieved old genetic information that allows us to reconstruct molecular evolution well beyond the usual time, "he said.

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

Prior to this discovery, the oldest sequenced DNA came from a 700,000 year old horse. At present, DNA data trace human evolution over the last 400,000 years, but the lineages that led to humans and modern chimpanzees have been ramified there are between 6 and 7 million years.

This means that scientists have no genetic information for more than 90% of the evolutionary path that has led to modern humans. For example, the genetic links between modern humans and missing humans Homo erectus are still unknown because everything is based on anatomical information – as opposed to genetic.

This is because the DNA degrades – unless the samples are preserved in the permafrost – after about 500,000 years. In contrast, proteins can last for millions of years and, using mass spectrometry, scientists can individually identify proteins and determine their age.

"Protein sequencing based on mass spectrometry will enable us to retrieve reliable and rich genetic information on mammalian fossils that are millions of years old," said co-author Professor Jesper Olsen. University of Copenhagen.

"This is the only technology that can provide the robustness and precision needed to sequence small amounts of protein of this age.

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

Scientists say this discovery could result in significant changes in our understanding of the changing world.

"This research is a game changer that opens up many options for future evolutionary studies on humans and mammals. It will revolutionize molecular biomarker-based evolutionary study methods and open up a whole new field of ancient biomolecular studies, "said lead author Professor Eske Willerslev of the University of Cambridge.