Unparalleled.. What did the world’s oldest DNA chains reveal?

Dubai, United Arab Emirates (CNN) — Ice Age sediments in northern Greenland have yielded the world’s oldest DNA sequences.

Two million-year-old DNA samples have revealed that the now lifeless polar region was once home to rich plant and animal life, according to new research published in the journal Nature on Wednesday.

The researchers concluded that the combination of trees and animals indicates a previously unknown type of ecosystem, with no analogues in the present world.

The discovery was led by a group of scientists in Denmark, who were able to detect and retrieve environmental DNA in trace amounts from sediments taken from the Copenhaven Formation, at the mouth of a fjord in the Arctic Ocean, far north of Greenland, during an expedition in 2006.

The genetic material revealed dozens of plants and other creatures not previously discovered at the site, based on what is known from fossil records and pollen.

This discovery broke the previous record for the world’s oldest DNA, set by research published last year on genetic material extracted from the teeth of mammoths that roamed the Siberian steppes more than a million years ago, in addition to the previous record for DNA from sediments.

An artist’s view of what the Cape Copenhaven Formation in northern Greenland might have looked like 2 million years ago. , plain_textCredit: Beth Zaiken

fertile ecosystem

Professor Eske Willerslev, Associate Professor at St John’s College, University of Cambridge and Director of the Lundbeck Foundation GeoGenetics Centre, said: “While DNA from animal bones or teeth may shed light on individual species, environmental DNA has enabled scientists to build up a picture of an ecosystem.” comprehensive”.

He continued, “Only a few plant and animal fossils were found in the area… It was very exciting when we recovered the DNA to see a very different ecosystem. People knew from the large fossils that there were trees, but the DNA allowed us to identify many more taxa and species.” Organisms”.

The researchers were surprised to discover that cedars similar to those found in British Columbia today could have been growing in the Arctic alongside species such as pine, which now grow in the far north of the planet.

No carnivore DNA has been found, but predators such as bears, wolves or even saber-toothed tigers are believed to have been present in the ecosystem.

The truly groundbreaking discovery “went to the limit” in the field of ancient DNA, said Love Dalen, a professor at the Center for Paleogenetics at Stockholm University, who worked on mammoth tooth DNA research and was not involved in this study.

“This is a really cool paper,” he told CNN. “It can tell us about the formation of ecosystems at different points in time, which is really important for understanding how past changes in climate affected biodiversity at the species level. This is something DNA can’t.” revealed to the animal.

Willerslev said the 16-year study was the longest project of its kind he and most of his team of researchers have been involved in.

Extracting the fragments of the genetic code from the sediments took a great deal of work, after the team demonstrated for the first time that DNA was hidden in the clay and quartz deposits and could be separated from it.

The fact that the DNA attached to the metal surfaces was likely the reason it survived so long, the researchers said.

Willersev continued: “We re-examined these samples and failed … and called it the ‘Copenhaven Formation curse’ in the laboratory.”

Further study of environmental DNA, in this time period, may help all scientists understand how different organisms can adapt to climate change.

“It’s a climate we expect to encounter on Earth due to global warming and it gives us an idea of ​​how nature will respond to rising temperatures,” he said.

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