An international team of scientists has recovered the oldest DNA from a variety of plants. fish, and ancient mastodon. The 2-million-year-old DNA shows the unrecognizable Greenland millions of years ago when it was once a lush forest, which served as home to trees and other organisms.
The previously recorded oldest sequenced DNA was from a one-million-year-old Siberian mammoth. But after an eight-year effort to recover DNA from the frozen interior of the island, researchers said that they have managed to sequence gene fragments left by dozens of species and washed into sediment layers a long time ago.
Oldest DNA Sequenced Reveal Ancient Arctic Ecosystem
MIT Technology Review reports that the genetic findings paint a picture of an era when Greenland was covered with flowering plants and cottonseed trees, which provide clues as to climates adapted as the world gets warmer.
Lead author of the study Eske Willerslev of the University of Copenhagen said that sequencing the DNA provided a map of where and how to edit the genetics of plants to make them resistant to climate change, adding that the ancient DNA could be a road map to help plant species adapt to global warming.
Geographer Mikkel Pedersen, a co-author of the new analysis, said that scientists have carefully reconstructed an unprecedented glimpse into the ancient Arctic landscape that has no modern equivalent. The team said that it was neither a boreal forest, like those found in modern Scandinavia, nor it was a temperate forest. Rather, the ancient, forested landscape is a unique mix.
They found traces of dozens of different plant species, insects, marine species, and nine vertebrates whose fossils had never been seen in Greenland that ranged from small rodents to rabbit ancestors to a single trace of a mastodon.
The DNA paints a complex picture of a fully integrated ecosystem that existed in an era when the Arctic region was between 11 to 17 degrees Celsius (about 20 to 30 Fahrenheit) warmer than today. It was a period that provides the closest future analogs of what could happen to Earth in the coming decades due to climate change.
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How DNA Sequencing Helped Their Research
The remarkable research was about 20 years in the making, as per National Geographic. Some members of the team visited the Kap Kobenhavn site in northern Greenland in 2006 to check on the prospect of frozen dirt that might contain the frozen DNA.
The site was discovered 40 years ago and scientists have begun studying to look for clues of what the region might have looked like in the past. They uncovered small fragments of ancient birch branches and cones, as well as a piece of rabbit tooth, and other evidence of a forested landscape from the ancient Arctic sediments.
But the fact that some DNA remains of a mastodon were found in the area surprised the team. The mastodon was an extinct relative of the elephant that lived millions of years ago. They told Nature that mastodons and reindeer should not have survived in those areas, but the DNA sequencing says otherwise.
The samples were recoverable thanks to freezing temperatures and the fact that they were in clay and quartz, which slowed down DNA degradation significantly that preserved them even after 2 million years. In other words, the research is a tremendous achievement of modern science thanks to the cutting-edge gene sequencing technologies that provide a snapshot of the planet's distant past.
They discussed their analysis, titled "A 2-million-year-old ecosystem in Greenland uncovered by environmental DNA," in full in the journal Nature.
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