The oldest DNA ever found was used by researchers to shed light on life two million years ago in Greenland's northernmost region. It was once a lush landscape of trees and vegetation with a variety of animals, including the now-extinct mastodons. The tip of northern Greenland is now a desolate Arctic desert.
eDNA
Kurt Kjær, a University of Copenhagen geologist and glacier expert, said that the study provides access to an essentially lost past. Kjær is the lead author of the study.
Since it was difficult to find animal fossils, the scientists extracted environmental DNA, or eDNA, from soil samples. This is the genetic material that living things release into the environment, such as through spittle, waste, hair, or decaying animal remains.
It can be difficult to study DNA that is extremely old because genetic material degrades over time, leaving only tiny fragments for researchers to study.
Eske Willerslev, a University of Cambridge geneticist, explained that the researchers were able to extract genetic data from the small, damaged pieces of DNA using the most recent technology. Willerslev is the senior author of the paper.
In their research, they looked for matches by comparing the DNA with that of various species.
Peary Land Vegetation and Wildlife
According to Kjær, the samples were taken from a sedimentary formation in Peary Land, which is currently a polar desert, known as the Kap København formation.
Willerslev said that Temperatures in this area rose dramatically during a period of intense climate change that occurred millions of years ago. Before the climate cooled and the finds were frozen into permafrost, sediment probably accumulated at the site for tens of thousands of years.
The delicate DNA fragments would be preserved by the cold environment-until 2006 when scientists started drilling out the samples.
The area was home to an unusual variety of plant and animal life during the warm period when average temperatures were 20 to 34 degrees Fahrenheit higher than they are today. The DNA fragments indicate a mixture of plants from the Arctic, such as willow shrubs and birch trees, and plants that typically prefer warmer climates, such as firs and cedars, AP News reports.
Additionally, the DNA revealed traces of various animals, such as lemmings, hares, reindeer, and geese. The only previous traces of animal life at the location were a dung beetle and some hare remains, according to Willerslev.
One major surprise, according to Kjær, was discovering DNA from the mastodon, an extinct species that resembles a cross between an elephant and a mammoth.
There have already been a lot of mastodon fossils discovered in temperate forests in North America. According to Willerslev, that is located much further south and across an ocean from Greenland.
Mastodons in Greenland
Love Dalen, an evolutionary genomics researcher at Stockholm University, stated that he never in a million years would have imagined discovering mastodons in northern Greenland. Dalen didn't take part in the research.
Researchers were able to learn more about marine life during this time period because the sediment accumulated in a fjord's mouth. The DNA indicates the presence of horseshoe crabs and green algae, indicating that the local waters were presumably much warmer at the time.
According to the data at hand, it is difficult to determine whether these species actually coexisted or if DNA from various parts of the environment was mixed together, according to Laura Epp, an eDNA specialist at the University of Konstanz in Germany who was not engaged in the research.
However, according to Epp, this kind of DNA study is useful for revealing "hidden diversity" in prehistoric landscapes.
Willerslev believes that these organisms' DNA may provide a "genetic roadmap" to assist modern humans in adapting to global warming because they thrived during a period of dramatic climate change.
Dalen anticipates that ancient DNA research will continue to delve further into the past. He contributed to the research that established the previous record for "oldest DNA"-from a mammoth tooth that is about a million years old, PhysOrg reports.
The study by Kjær, Willerslev, and their colleagues was recently published in the journal Nature.
Related article: Oldest DNA Ever Discovered in Antarctica is About 1 Million Years Old, Study Shows
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