{"id":21724,"date":"2022-12-07T18:48:34","date_gmt":"2022-12-07T18:48:34","guid":{"rendered":"https:\/\/mailinvest.blog\/index.php\/2022\/12\/07\/oldest-dna-reveals-life-in-greenland-2-million-years-ago\/"},"modified":"2022-12-07T18:48:34","modified_gmt":"2022-12-07T18:48:34","slug":"oldest-dna-reveals-life-in-greenland-2-million-years-ago","status":"publish","type":"post","link":"https:\/\/mailinvest.blog\/index.php\/2022\/12\/07\/oldest-dna-reveals-life-in-greenland-2-million-years-ago\/","title":{"rendered":"Oldest DNA reveals life in Greenland 2 million years ago"},"content":{"rendered":"

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NEW YORK — <\/span>Scientists discovered the oldest known DNA and used it to reveal what life was like 2 million years ago in the northern tip of Greenland. Today, it\u2019s a barren Arctic desert, but back then it was a lush landscape of trees and vegetation with an array of animals, even the now extinct mastodon.<\/p>\n

\u201cThe study opens the door into a past that has basically been lost,\u201d said lead author Kurt Kj\u00e6r, a geologist and glacier expert at the University of Copenhagen.<\/p>\n

With animal fossils hard to come by, the researchers extracted environmental DNA, also known as eDNA, from soil samples. This is the genetic material that organisms shed into their surroundings \u2014 for example, through hair, waste, spit or decomposing carcasses.<\/p>\n

Studying really old DNA can be a challenge because the genetic material breaks down over time, leaving scientists with only tiny fragments. <\/p>\n

But with the latest technology, researchers were able to get genetic information out of the small, damaged bits of DNA, explained senior author Eske Willerslev, a geneticist at the University of Cambridge. In their study, published Wednesday in the journal Nature, they compared the DNA to that of different species, looking for matches.<\/p>\n

The samples came from a sediment deposit called the Kap K\u00f8benhavn formation in Peary Land. Today, the area is a polar desert, Kj\u00e6r said.<\/p>\n

But millions of years ago, this region was undergoing a period of intense climate change that sent temperatures up, Willerslev said. Sediment likely built up for tens of thousands of years at the site before the climate cooled and cemented the finds into permafrost. <\/p>\n

The cold environment would help preserve the delicate bits of DNA \u2014 until scientists came along and drilled the samples out, beginning in 2006.<\/p>\n

During the region’s warm period, when average temperatures were 20 to 34 degrees Fahrenheit (11 to 19 degrees Celsius) higher than today, the area was filled with an unusual array of plant and animal life, the researchers reported. The DNA fragments suggest a mix of Arctic plants, like birch trees and willow shrubs, with ones that usually prefer warmer climates, like firs and cedars.<\/p>\n

The DNA also showed traces of animals including geese, hares, reindeer and lemmings. Previously, a dung beetle and some hare remains had been the only signs of animal life at the site, Willerslev said.<\/p>\n

One big surprise was finding DNA from the mastodon, an extinct species that looks like a mix between an elephant and a mammoth, Kj\u00e6r said. <\/p>\n

Many mastodon fossils have previously been found from temperate forests in North America. That\u2019s an ocean away from Greenland, and much farther south, Willerslev said.<\/p>\n

\u201cI wouldn\u2019t have, in a million years, expected to find mastodons in northern Greenland,\u201d said Love Dalen, a researcher in evolutionary genomics at Stockholm University who was not involved in the study. <\/p>\n

Because the sediment built up in the mouth of a fjord, researchers were also able to get clues about marine life from this time period. The DNA suggests horseshoe crabs and green algae lived in the area \u2014 meaning the nearby waters were likely much warmer back then, Kj\u00e6r said.<\/p>\n

By pulling dozens of species out of just a few sediment samples, the study highlights some of eDNA\u2019s advantages, said Benjamin Vernot, an ancient DNA researcher at Germany\u2019s Max Planck Institute for Evolutionary Anthropology who was not involved in the study. <\/p>\n

\u201cYou really get a broader picture of the ecosystem at a particular time,\u201d Vernot said. \u201cYou don\u2019t have to go and find this piece of wood to study this plant, and this bone to study this mammoth.\u201d<\/p>\n

Based on the data available, it\u2019s hard to say for sure whether these species truly lived side by side, or if the DNA was mixed together from different parts of the landscape, said Laura Epp, an eDNA expert at Germany\u2019s University of Konstanz who was not involved in the study.<\/p>\n

But Epp said this kind of DNA research is valuable to show \u201chidden diversity\u201d in ancient landscapes.<\/p>\n

Willerslev believes that because these plants and animals survived during a time of dramatic climate change, their DNA could offer a \u201cgenetic roadmap\u201d to help us adapt to current warming.<\/p>\n

Stockholm University’s Dalen expects ancient DNA research to keep pushing deeper into the past. He worked on the study that previously held the \u201coldest DNA\u201d record, from a mammoth tooth around a million years old. <\/p>\n

\u201cI wouldn\u2019t be surprised if you can go at least one or perhaps a few million years further back, assuming you can find the right samples,\u201d Dalen said.<\/p>\n

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute\u2019s Science and Educational Media Group. The AP is solely responsible for all content.<\/p>\n<\/div>\n