Cambridge scientists discover two-million-year-old DNA

The world's oldest DNA ever sampled was found in Ice Age sediment in northern Greenland

An artist's rendition of Kap København Formation two million years ago. Photo: Beth Zaiken
Beta V.1.0 - Powered by automated translation

Scientists have unearthed two-million-year-old DNA for the first time, which could open a new chapter in the history of evolution and help predict the effects of modern global warming.

The team from the University of Cambridge discovered microscopic fragments of environmental DNA in Ice Age sediment in northern Greenland.

The fragments are one million years older than the previous record for DNA sampled from a Siberian mammoth bone.

They discovered 41 usable samples that were hidden in clay and quartz, according to the research published in Nature.

The ancient DNA has now been used to map a two-million-year-old ecosystem which weathered extreme climate change, the team said.

The results could help predict the long-term environmental toll of current global warming.

The discovery was made by a team of scientists led by Prof Eske Willerslev from St John’s College at the University of Cambridge, and geology expert Prof Kurt Kjær, director of the Lundbeck Foundation GeoGenetics Centre at the University of Copenhagen.

“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,” Prof Willerslev said.

“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 organic layers show traces of the rich plant flora and insect fauna that lived two million years ago at Kap København in North Greenland. Photo: Professor Svend Funder

The samples, a few millionths of a millimetre long, were taken from the København Formation, a sediment deposit almost 100m thick, which was found in the mouth of a fjord in the Arctic Ocean in Greenland’s northernmost point.

“The ancient DNA samples were found buried deep in sediment that had built up over 20,000 years,” Prof Kjær said.

“The sediment was eventually preserved in ice or permafrost and, crucially, not disturbed by humans for two million years.”

An artist’s reconstruction of the landscape surrounding the Kap København formation today. Photo: Beth Zaiken

The climate in Greenland at the time varied between Arctic and temperate and was between 10°C and 17°C warmer than Greenland is today. The sediment had built up metre by metre in a shallow bay.

Evidence of animals, plants and microorganisms, including reindeer, hares, lemmings, birch and poplar trees was discovered.

Researchers even found that Mastodon, an Ice Age mammal, roamed as far as Greenland before it later became extinct.

Previously it was thought the range of the elephant-like animals did not extend as far as Greenland from North and Central America.

A team of 40 researchers from Denmark, the UK, France, Sweden, Norway, the US and Germany, worked on the project, which saw them comparing every single DNA fragment with extensive libraries of DNA collected from present-day animals, plants and microorganisms.

Remains of wooden branches from the forest that grew at Kap København two million years ago. Photo: Professor Svend Funder

Eventually a picture began to emerge from the DNA of trees, bushes, birds, animals and microorganisms.

They said some of the DNA fragments were easy to classify as predecessors to present-day species, but others could only be linked at genus level, and some originated from species impossible to place in the DNA libraries of animals, plants and microorganisms still living in the 21st century.

The two-million-year-old samples will also help academics build a picture of a previously unknown stage in the DNA evolution of a range of species still in existence today.

Updated: December 12, 2022, 12:50 PM
EDITOR'S PICKS
NEWSLETTERS