Two million-year-old fragments have been discovered in Greenland in what is a historic research discovery. A Danish-led research group, in which Norwegian researchers have also contributed, has found DNA from an entire ecosystem that existed two million years ago. The study has been published in the journal Nature. What exactly is DNA? DNA is the genetic material found in all cells, and has two main functions: DNA contains recipes that determine how the organism should look and function. This could be, for example, the color of a flower or the blood type of a person. These recipes are called genes. DNA is called genetic material because these recipes are passed on (inherited) from one generation to the next. All DNA must copy itself when new cells are formed by cell division. The new cells have exactly the same DNA. The DNA copying itself is called DNA replication. The name DNA is an abbreviation that stands for deoxyribonucleic acid, or deoxyribonucleic acid in Norwegian. DNA is a chemical substance, a nucleic acid, which consists of large molecules. DNA is shaped like a long, double-stranded helix where the genes are arranged one after the other. These strands are packed tightly together in chromosomes. The number of chromosomes varies from species to species. For example, humans usually have 46 chromosomes, while fruit flies have eight chromosomes. Breaking boundaries In 2021, researchers at UiT announced the discovery of the world’s oldest DNA. It came from mammoths that lived about a million years ago. Researchers at the University of Tromsø have also contributed to the work with the new DNA discovery, which is therefore twice as old. – DNA can be broken down quickly, but we have shown that under the right circumstances we can now go further back in time than anyone could have dared to imagine, says Professor Eske Willerslev. Among other things, he is director of the Lundbeck Foundation GeoGenetics Center at the University of Copenhagen. The researchers have obtained the DNA from sediments. Hereditary material from mastodon, tuja, birch, reindeer, geese and more tells about the ecosystem in Greenland two million years ago. Back then, Greenland was a much warmer place. Professor Inger Greve Alsos at UiT is one of the researchers behind the DNA study. Photo: UiT – The Arctic University of Norway Researchers Inger Greve Alsos and Alexandra Rouillard at UiT have participated in the study from the Norwegian side. – We are constantly pushing the boundaries of what is possible to explore, says Alsos to news. – This is the time when the Arctic begins to form, when the cooling of the earth began, says the professor. There was a climate in northern Greenland at the time where it must have been warm enough for trees, she says. We are talking about species that are not at all associated with the northern areas today. Today, approximately 81 percent of Greenland is covered by ice all year round, according to Store Norske Leksikon. – There are hardly enough bushes this far north today, and certainly no trees, says Alsos. Can see climate changes over time Alsos and her colleagues have spent a full five years creating a DNA library of plant species by sequencing plants in the herbarium at Tromsø Museum. By matching two million-year-old DNA against this and other DNA libraries, the researchers have managed to reconstruct the ecosystem. Alsos says that this type of research is the only way scientists have to look at climate change over a long period of time. In modern times, there is only data that goes back up to a hundred years, she says. – Here we have a direct insight into the evolution. Ancient DNA is the only way to investigate long-term effects, because it is the only data you have. She says that in Norway, for example, it took several thousand years before many of the species we know today managed to take root here after the Ice Age. Researchers have found DNA from an entire ecosystem that is two million years old in Greenland. The mastodon elephant, reindeer and hare lived there in a climate that was quite different from what we know today. Illustration: BETH ZAIKEN – If it was only the temperature that determined, then one would have expected all the species to be there as long as it was warm enough. But it is not like that, she says. Together with colleagues, this is something she will research in the future. The DNA discovery also showed that mastodons lived in Greenland at this time. The huge elephant animal became extinct around 10,000 years ago. The study thus shows that these Ice Age animals spread all the way up to Greenland. The researchers also found DNA from reindeer, hares, geese and lemurs. These are animals that are still found in Greenland today. Cape Copenhagen in Greenland as it looks today. The contrast to the lush image with mastodon and green plants and trees is great. Today, this place is an arctic desert with low biodiversity. Illustration: Beth Zaiken Can be beaten again The field is only about 20 years old, says Alsos, and there may be more records. In any case, there is a lot of exciting research that remains to be done from the last two million years, she says. – Within the professional environment, we haven’t really read that much in such old tests. Because we have not known that it is actually possible to find DNA in them. The vast majority of studies of ancient DNA are less than 50,000 years old. – I think that we will now seek out more places with sediments that are older and see what else we can find.
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The world’s oldest DNA found in Greenland by Danish researchers with help from UiT in Norway – news Troms and Finnmark
