Scientists have identified the oldest DNA ever discovered, revealing a complex ecosystem that existed in modern Greenland two million years ago in the process, according to the results of a new study published in the journal Nature. Nature.
The double helix-shaped molecule Deoxyribonucleic acid (or DNA for short) is found in nearly every cell of our human bodies and the plants and animals that live on our planet.
Each DNA molecule contains within it a genetic code unique to each individual and acts as a vital instruction manual for our cells, helping to govern how our bodies develop and function. It’s also an incredibly useful molecule for scientists who want to unravel the mysteries of the ancient past.
That’s because by looking for DNA fragments in well-preserved samples, in some cases dating back hundreds of thousands of years, researchers can determine which animal or plant species existed in a particular window in Earth’s evolutionary history.
Once these specimens are identified, scientists can match the genetic codes found in the DNA to the closest present-day specimens to determine what type of animal or species they belong to. In this way, humanity can build a picture of all ecosystems lost in the relentless passage of time and gain valuable insights into the evolution of life on our planet.
Unfortunately, this technique is limited to the lifetime of a DNA molecule. As cells begin to die, enzymes begin to break the bonds that hold these vital molecules together. Under normal conditions in animals, this process of decay would render DNA useless in about 521 years.
However, samples are known to survive much longer when the right conditions allow for rapid and stable preservation of DNA.
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In the new study, scientists were able to recover 41 ancient DNA samples from the mouth of a fjord located at the northernmost point of Greenland, where the land mass meets the Arctic Ocean. Each of the DNA samples excavated from the rock known as the København Formation was only a few millionths of a millimeter long and was covered with a protective shell of clay and quartz.
By applying a combination of radiocarbon and molecular dating techniques, the international team of more than 40 scientists were able to estimate that DNA is, on average, about 2 million years old. That makes them 1 million years older than the previous record holder for ancient DNA extracted from the bone of a Siberian mammoth.
“Ancient DNA samples were found buried deep in sediment that formed over 20,000 years.” comments Professor Kurt Kjaer Leading the research, Dr. from the University of Copenhagen. “The sediment was eventually preserved in ice or permafrost and, most importantly, undisturbed by humans for two million years.”
After meticulously comparing DNA with data from the 21st century, the team was able to decipher the fingerprints of a thriving, ancient ecosystem locked inside the samples.
When the København Formation was formed about two million years ago, Greenland was a more hospitable place, roughly 10-17 degrees Celsius warmer than it is today.
DNA evidence has revealed the existence of numerous species of plant life in the ancient environment, including forms of poplar and birch. Among these trees roamed lemmings, reindeer, rabbits, and even giant elephant creatures called Mastadon. There were also fragments of DNA that could not be matched with any modern animal or plant.
Most of the samples have been waiting to be analyzed since they were first collected from the Greenland field in 2006.
“Until next generation DNA extraction and sequencing equipment was developed, we were able to detect and identify extremely small and damaged DNA fragments in sediment samples,” said Professor Kjær. It can map a two-million-year-old ecosystem.”
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The scientists behind the new study believe that the relatively warm environment of ancient Greenland is comparable to the temperatures we may see in the future as a result of global warming. modern day climate change It is recognized as a serious threat to biodiversity on a global scale, and the speed with which species adapt to changing environments and warming temperatures will be key to their survival.
“The data suggest that more species can evolve and adapt to wildly varying temperatures than previously thought,” said Assistant Professor Mikkel Pedersen of the Lundbeck Foundation Center for GeoGenetics, co-author of the new paper. “But most importantly, these results show that they need time to do that.”
It is hoped that by analyzing the DNA of ancient trees and plants, scientists can unravel the secrets of how they adapted to their warm environments and potentially learn how to make today’s endangered species more resilient to climate change. .
Going forward, the team hopes to discover more examples of truly ancient DNA in clay from Africa that could shed light on humanity’s earliest ancestors.
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Anthony is a freelance writer covering science and video game news for IGN. He has more than eight years of experience reporting breakthroughs in multiple scientific fields and has absolutely no time for your antics. Follow him on Twitter @BeardConGamer
Image Credit: Beth Zaiken
