Scientists have identified two-million-year-old DNA for the first time – breaking the previous record by one million years.
The microscopic fragments, found in ice age sediment in northern Greenland, are twice the age of the previous oldest DNA, which was sampled from a Siberian mammoth bone.
The DNA from Greenland has been used to map a two-million-year-old ecosystem and it is hoped it could give clues on how best to counteract the “devastating impact of global warming”.
Scientists also discovered evidence of animals, plants and microorganisms including reindeer, hares, lemmings, birch and poplar trees.
Researchers found Mastodon, an ice age mammal, roamed as far as Greenland before becoming extinct.
It was previously thought the range of the elephant-like animals did not extend that far from its known North and Central America origins.
Professor Willerslev, a fellow of Cambridge University’s St John’s College, said: “A new chapter spanning one million extra years of history has finally been opened and for the first time we can look directly at the DNA of a past ecosystem that far back in time.
“DNA can degrade quickly but we’ve shown that under the right circumstances, we can now go back further in time than anyone could have dared imagine.”
The 41 usable DNA samples were found hidden in clay and quartz in the Kobenhavn Formation, a sediment deposit almost 100 metres thick, tucked in the mouth of a fjord in the Arctic Ocean.
Each sample is a few millionths of a millimetre long.
Professor Kurt H Kjaer, of Copenhagen University’s Lundbeck Foundation GeoGenetics Centre, said: “The ancient DNA samples were found buried deep in sediment that had built-up over 20,000 years.
“The sediment was eventually preserved in ice or permafrost and, crucially, not disturbed by humans for two million years.”
Detective work by a team of 40 researchers from Denmark, the UK, France, Sweden, Norway, the USA and Germany unlocked the secrets of the DNA fragments.
“Expeditions are expensive and many of the samples were taken back in 2006 when the team were in Greenland for another project. They have been stored ever since,” said Prof Kjaer.
“It wasn’t until a new generation of DNA extraction and sequencing equipment was developed that we’ve been able to locate and identify extremely small and damaged fragments of DNA in the sediment samples.”
He continued: “It is possible that genetic engineering could mimic the strategy developed by plants and trees two million years ago to survive in a climate characterised by rising temperatures and prevent the extinction of some species, plants and trees.
“This is one of the reasons this scientific advance is so significant because it could reveal how to attempt to counteract the devastating impact of global warming.”
Prof Willerslev said it “may be possible that clay may have preserved ancient DNA in warm, humid environments in sites found in Africa”.
“If we can begin to explore ancient DNA in clay grains from Africa, we may be able to gather ground-breaking information about the origin of many different species – perhaps even new knowledge about the first humans and their ancestors – the possibilities are endless,” he said.
The research is published in the journal Nature.
