MOSCOW, 17 Feb – RIA Novosti. Scientists have extracted and sequenced DNA from molars of three mammoths found in northeastern Siberia. The finds are more than one million years old. The results of the study made it possible to trace the early evolutionary lines of the Eurasian and North American branches of mammoths. The article was published in the journal Nature.
About a million years ago, there were no woolly or Colombian mammoths that lived in Eurasia and North America during the last ice age. This was the time of their predecessor, the ancient steppe mammoth. How it was related to later species was still not known.
The researchers were able to extract mitochondrial DNA from the teeth of three ancient mammoths that were found in the Siberian permafrost. Named for their places of discovery, they have the following age: Krestovka – about 1.65 million years old, Adycha – about 1.34 million years old, and Chukochya – 0.87 million years old.
The genomic data of these samples suggest that two independent mammoth lines existed in Eastern Siberia in the early Pleistocene. The sequencing results showed that two mammoths – Adycha and Chukochya – belong to the lineage from which the Eurasian and North American woolly mammoths originated, and Krestovka represents a previously unknown line.
According to the authors' estimates, the Krestovka lineage split from the genome of other mammoths approximately 2.66-1.78 million years ago and gave rise to the first North American mammoths. And the Columbian mammoth, or Columbus mammoth, that lived in North America during the last ice age, was a hybrid of the woolly mammoth and this previously unknown genetic line.
“This came as a complete surprise to us. All previous studies suggested that at that time there was only one type of mammoth in Siberia, called the steppe mammoth. But our DNA analyzes show that there were two different genetic lines, which we here call Adychinsky and Krestovsky mammoths. We cannot yet say for sure, but we think that these are two different species, “lead author Tom van der Valk of the Center for Paleogenetics in Stockholm and the University of Uppsala quoted in a press release from Stockholm University.
“This is an important discovery. It seems that the Colombian mammoth, one of the most iconic species of the Ice Age in North America, evolved from hybridization that took place about 420 thousand years ago,” adds Patrícia Pečnerová, another author of the article, from the Swedish Museum. natural history.
The study, which was conducted at the Center for Paleogenetics in Stockholm, was the result of international collaboration of 22 scientists from nine countries. For the first time in the history of paleogenetics, it was possible to extract DNA from biomaterial over a million years old. Earlier, the age of the oldest sequenced DNA of an ancient horse was estimated at 780-560 thousand years.
“This DNA is incredibly ancient. These mammoths lived before there were humans and Neanderthals,” says research lead professor of evolutionary genetics Love Dalén.
Extracting ancient DNA was challenging, according to the authors – only a tiny amount of DNA remained in the samples, and it disintegrated into very small fragments.
The authors note that their study also provided new insights into how mammoths adapted to life in cold conditions and how this adaptation affected speciation. The results showed that gene variants associated with life in the Arctic and affecting hair growth, thermoregulation, body fat accumulation, cold tolerance and circadian rhythms were already present in ancient mammoths more than a million years ago, long before they developed long hair.