Teeth from Siberian mammoths yield oldest DNA ever recovered

Geneticist Tom van der Valk of SciLifeLab in Sweden, the study's first author, said it appears that members of the Krestovka lineage were the first mammoths to migrate from Siberia into North America over a now-disappeared land bridge about 1.5 million years ago, with woolly mammoths later migrating about 400,000 to 500,000 years ago.



DNA analyses showed that genetic variants associated with enduring frigid climes such as hair growth, thermoregulation, fat deposits, cold tolerance and circadian rhythms were present long before the origin of the woolly mammoth.

The oldest of the three, discovered near the Krestovka river, was approximately 1.2 million years old. Another, from near the Adycha river, was approximately 1 to 1.2 million years old. The third, from near the Chukochya river, was roughly 700,000 years old.

Until now, the oldest DNA came from a horse that lived in Canada's Yukon territory about 700,000 years ago. By way of comparison, our species, Homo sapiens, first appeared roughly 300,000 years ago.

Ancient DNA can help fill in the blanks but is highly perishable. Sophisticated new research techniques are enabling scientists to recover ever-older DNA.


"It would be a wild guess, but a maximum of two to three million years should be doable," Dalén said. That could shed light on some bygone species but would leave many others unattainable - including the dinosaurs, who went extinct 66 million years ago.

The researchers gained insights into mammoth evolution and migration by comparing the DNA to that of mammoths that lived more recently. The last mammoths disappeared roughly 4,000 years ago.


The oldest of the three specimens, the Krestovka mammoth, belonged to a previously unknown genetic lineage that more than 2 million years ago diverged from the lineage that led to the well-known woolly mammoth.