The oldest mammoth, named Krestovka, was found to be approximately 1.65 million years old and will help shed light on how North America’s mammoths evolved.
Scientists have discovered the world's oldest DNA that is easily more than a million years old. It belongs to the steppe mammoth, which is a predecessor to the more well-known woolly mammoth. The DNA was recovered from the molar remains of three mammoth specimens, dating to the Early and Middle Pleistocene subepochs. A study with these findings was published in Nature Research Journals. Two of these specimens were found to be more than a million years old. The oldest DNA recovered previously was dated from 780,000 to 560,000 years ago. This marks a great potential for studying evolutionary processes such as speciation, the study stated.
Mammoth teeth preserved in eastern Siberian permafrost have produced the oldest ancient DNA on record - up to 1.6 million years old. https://t.co/pwJUJ4MD8p— Nature News & Comment (@NatureNews) February 17, 2021
"This DNA is incredibly old. The samples are a thousand times older than Viking remains, and even predate the existence of humans and Neanderthals," Love Dalén, a professor of evolutionary genetics at the Centre for Palaeogenetics in Stockholm, and lead author of the study said. The teeth have been preserved because it was buried for more than a million years in the Siberian permafrost and was first discovered in the 1970s by Russian paleontologist Andrei Sher. Extracting DNA from it proved to be challenging since it had degraded into very small fragments. Only minute amounts of DNA remained in the samples.
Co-author Tom van der Valk, an Uppsala University bioinformatician who worked on the study while at the Centre for Palaeogenetics in Stockholm, Sweden told National Geographic, “Breaking this somewhat magical barrier of more than one-million-years-old opens a new time window, so to say, and evolutionary perspective.” The findings from the DNA have shed light on how North America’s mammoths must have evolved. “If we look at higher-order organisms like vertebrates, I can’t think of a single example where people have sampled before the origin of a species,” Dalén said about how the mammoths as a hybrid species arose 400,000 to 500,000 years ago.
The third specimen was found to be the youngest of the trio and also one of the earliest woolly mammoths to be found. The Guardian reported that once the scientists conducted an age estimate from the genetic information, the oldest mammoth, named Krestovka, was found to be approximately 1.65 million years, while the second, Adycha, was about 1.34 million years old, and the youngest, Chukochya, was 870,000 years old. The researchers also said that there is a chance that Krestovka could be older considering the DNA they could retrieve is probably a more recent layer of sediment.
This mammoth tooth is 1.2 million years old.— Centre for Palaeogenetics (@CpgSthlm) February 17, 2021
We have recovered DNA from it.
This is the oldest DNA ever sequenced.
The results are published today in Nature:https://t.co/OaOTh7mOzo
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“Instead of there being one species [or lineage] of mammoth up in Siberia around 1-2 million years ago, it now looks like there are two,” Dalén told New Scientist. Mammoths were originally a tropical species that had origins in Africa and then moved out of Africa. The mammoths during Krestovka's age are believed to be the first to colonize North America. The steppe mammoths gradually gave rise to woolly mammoths in Siberia. These mammoths moved towards North America later to interbreed with the Krestovka mammoths that gave rise to the Columbian mammoths, which were a 50-50 mix of Krestovka and woolly mammoths. “What this piece of work is showing is that biology is messy,” Tori Herridge at the Natural History Museum in London said and added that a new species is not formed simply by a population splitting in two.
“That’s the million-dollar question,” Dalén said about being able to decode the secrets even older DNA holds. “We’ve seen the data we have, and I think it would be relatively easy to go beyond two million, if we just had a good specimen.”