The oldest DNA ever discovered reveals a thriving ecosystem lost to time
Scientists have identified the oldest DNA ever discovered, and in the process revealed a complex ecosystem that existed two million years ago in present-day Greenland, according to the results of a new study published in the journal. Nature.
The molecule in the form of a double helix Deoxyribonucleic acid (or DNA for short) is present in almost all the cells of our human body, and those of the plants and animals that inhabit our planet.
Each DNA molecule contains a genetic code that is unique to each individual and serves as a vital instruction manual for our cells that helps govern how our bodies develop and function. It is also an incredibly useful molecule for scientists seeking to decipher the secrets of the ancient past.
This is because researchers are able to determine which animal or plant species existed during a given window in Earth’s evolutionary history by looking for DNA remnants in well-preserved samples that, in some cases, date back to hundreds of thousands of years.
Once these samples are identified, scientists can match the genetic codes found in the DNA to their closest present-day counterparts, in order to determine what type of animal or species they belong to. In this way, humanity can build a picture of entire ecosystems that have been lost to the relentless passage of time and gain valuable insights into the evolution of life on our planet.
Unfortunately, this technique is limited by the lifetime of a DNA molecule. Once cells begin to die, enzymes go to work breaking the bonds that hold these vital molecules together. Under normal conditions in animals, this decay process will render DNA useless in about 521 years.
However, when the right conditions allow DNA to be preserved quickly and stably, samples are known to survive much longer.
“
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 extracted from the rock, known as the København Formation, was only a few millionths of a millimeter in length and was encased in 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 was able to estimate that the DNA was on average about 2 million years old. That makes them 1 million years older than the previous ancient DNA record holder, which was recovered from the bone of a Siberian mammoth.
“Ancient DNA samples were found buried deep in sediment that had accumulated over 20,000 years.” comments Professor Kurt Kjær from the University of Copenhagen, who helped lead the research. “The sediment was ultimately preserved in ice or permafrost and, crucially, was undisturbed by humans for two million years.”
After painstakingly comparing the DNA with 21st century data, the team was able to decode the fingerprints of a thriving, ancient ecosystem enclosed within the samples.
At the time the København Formation was created about two million years ago, Greenland was a more hospitable place, with temperatures roughly 10 to 17 degrees Celsius warmer than today.
The DNA evidence revealed the presence of countless species of plant life in the ancient environment, including forms of poplars and birches. Lemmings, reindeer, hares and even giant elephant creatures called Mastadon would have roamed among these trees. There were also fragments of DNA that could not be compared to any animal or plant today.
Many of the samples have been awaiting analysis since they were first collected at the Greenland site in 2006.
“It wasn’t until a new generation of DNA extraction and sequencing equipment was developed that we were able to locate and identify extremely small, damaged DNA fragments in sediment samples,” explained Prof. Kjær. “He said we were finally. able to map a two-million-year-old ecosystem.”
“
The scientists behind the new study believe that the relatively warm environment of ancient Greenland is comparable to the temperatures we could see in the future as a result of global warming. modern day climate change it is considered a serious threat to biodiversity on a global scale, and the rate at which species can adapt to changing environments and warming temperatures will be key to their survival.
“The data suggest that more species can evolve and adapt to highly variable temperatures than previously thought,” said Assistant Professor Mikkel Pedersen of the Lundbeck Foundation’s Center for Geogenetics, co-author of the new paper. “But fundamentally, 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 unlock the secrets of how they adapted to their hot environment and potentially learn how to make endangered species current ones are more resistant to climate change. .
Moving forward, the team hopes to discover more examples of truly ancient DNA in African clay that could shed light on humanity’s earliest ancestors.
Stay with IGN to keep up with the biggest and weirdest advances in the entire scientific world.
Anthony is a freelance contributor covering science and video game news for IGN. He has more than eight years of experience covering groundbreaking developments in multiple scientific fields and has no time for your shenanigans. Follow him on Twitter @BeardConGamer
Image credit: Beth Zaiken
#oldest #DNA #discovered #reveals #thriving #ecosystem #lost #time
