Scientists have discovered how the woolly mammoth managed to colonise the Arctic despite originally hailing from the tropics.
In an experiment reminiscent of Jurassic Park, a team of international scientists managed to reconstruct the haemoglobin of a woolly mammoth from the DNA found in a preserved bone.
By recreating the haemoglobin, the team -- which included biologist Professor Michi Hofreiter from the University of York as well as scientists from Australia, Canada, Germany and the USA -- were able to compare the mammoth haemoglobin with that of its closest living relative, the African and Asian elephants.
They discovered that the mammoth haemoglobin had three key amino acid differences that allowed oxygen to be released at lower temperatures more efficiently than in the elephant haemoglobin. Colder temperatures generally inhibit the release of oxygen to tissues.
The differences in the haemoglobin -- similar to protein structures found in reindeer and muskoxen -- allowed the mammoth to survive at much lower temperatures, enabling the species to move to higher latitudes and to eventually conquer the Arctic.
Professor Hofreiter said: “Our study is the first one to reconstruct an evolutionary important, adaptive trait from an extinct species using ancient DNA."
Scientists created the haemoglobin by converting the DNA into RNA -- a single strand of DNA -- and inserting it into E.coli bacteria to allow the protein to be replicated.
The study, which was carried out in collaboration with researchers from seven different institutions, was published in Nature Genetics.