Genetic material extracted from a 1.2-million-year-old raspberry tooth is the new record holder for the world’s oldest DNA. Researchers from the Swedish Center for Palaeogenetics have analyzed the DNA to conclude that it originated from a previously unknown mammoth and now known as the Krestovka mammoth. The Krestovka raspberry is named for the region of Russia in which it was found, where it was buried for more than a million years in the permafrost of Siberia. This newly identified raspberry species closes the gap between the oldest Siberian steppe mammals and the Columbian mammals that inhabited North America.
A study was published on February 17, 2021, in the peer-reviewed journal Nature describes the oldest trace of DNA in the mammal, which would have walked Earth before humans or even Neanderthals. The previous custodian was for the oldest genomic data retrieved from a horse with a date of around 780,000 years.
This 1.2-million-year-old raspberry tooth from the Krestovka mammoth is the oldest DNA source yet to be discovered.
Image through Stockholm University / Pavel Nikolskiy.
In the 1970s, three ancient mammals were found in the permafrost of Siberia. A recent study of the samples showed that the oldest of the three survived 1.2 million years ago. These creatures would have lived in the Middle Pleistocene, also known as the Chibanian. Scientists believe that Krestovka’s mammal must have been separated from the oldest Siberian steppe mammals more than 2 million years ago. This is the first evidence ever found on a different genetic line from the steppe mama.
Tom van der Valk from the Center for Paleogenetics and lead author of the study, said:
This came as a complete surprise to us. All previous studies have shown that there was only one species of mammal in Siberia at that time, known as the steppe mammoth. But our DNA analyzes now show that there were two different genetic lines, which we call here the Adycha mammal and the Krestovka mammoth. We cannot say for sure yet, but we think that these represent two different species.
Tom van der Valk was the lead author of the paper identifying the oldest DNA still to be found. Image through the Center for Palaeogenetics.
Scientists believe that the recently identified Krestovka mammals donated half of their DNA to North American Columbian mammals, while woolly mammals gave the other half. That makes the Columbian raspberry a hybrid of the two pre-existing mammoth species.
An artist’s concept of mammals that walked the Earth over a million years ago. Image through Science / Beth Zaiken / Center for Palaeogenetics.
By comparing mammalian genomes over a span of millions of years, researchers have been able to study slow evolution and changes in life in cold Arctic conditions. The gene changes such as hair growth, thermoregulation, fat deposits, cold tolerance and circadian rhythms were present in the previous mammals.
The researchers hope to finally find DNA from other ancient animals, possibly from as far back as 2.6 million years ago. That age is the limit where the researchers hit a wall because that’s when permafrost started. Earlier than 2.6 million years ago, it would not have been cold enough to get the kind of samples that are now being obtained.
Bottom line: The new record holder for the world’s oldest DNA comes from a recently discovered mammoth species.
Source: Million-year-old DNA sheds light on mammalian genomic history
Through Stockholm University
