DNA discovery reveals ‘lost’ 2 million-year-old ecosystem

A core of ice age sediments from northern Greenland yielded the world’s oldest DNA sequences. The specimens, estimated to be 2 million years old, reveal that a now-dead arctic region was once home to rich plant and animal life, including mammals, according to research published Wednesday in the journal Nature(7).

The mix of temperate vegetation with Arctic fauna and flora suggests the existence of an ecosystem that is not equivalent to any of the modern ecosystems and could serve as a genetic roadmap for how different species might adapt to a warmer climate.

The ancient ecosystem included rabbits, reindeer, geese, and birch trees, as well as elephant-like mammals known as mastodons. The discovery by scientists in Denmark makes it possible to detect and recover DNA from the environment in small pieces of sediment taken from the mouth of a fjord in the København Formation in the Arctic Ocean during the 2006 expedition.

The scientists compared DNA fragments with DNA banks collected from extinct and still-living animals, plants and microorganisms. The genetic material has revealed several plants and creatures that have yet to be identified in the area.

“The first thing that strikes us when we look at this data is this mastodon and its presence in the far north, far north of what we know as its native range,” said study co-author Mikkel Pedersen, an assistant professor at the center. For Geogenetics of the Lundbeck Foundation at the University of Copenhagen at a press conference.

ecosystem

The DNA of the environment is what allows scholars to form an opinion about this ecosystem. According to Professor Eske Willerslev, a fellow at Cambridge University’s St John’s College and director of the Lundbeck Foundation Center for GeoGenetics, the ecological community the researchers reconstructed existed at a time when temperatures were 10 to 17 degrees Celsius warmer than Greenland today.

“Only a few fossils of plants and animals were found at the site. It was exciting to see this very, very diverse ecosystem. People knew there were trees, some kind of forest above the macrofossils, but DNA allowed us. Identify more taxa[types of living organisms],” said Willerslev, who led the study. ” said.

Scientists were surprised to discover that the cedar tree species found in the UK today may have grown in the Arctic alongside species such as larch, which currently grows in the northernmost parts of the planet. Carnivore DNA has not been found, but they believe predators — such as bears, wolves and even saber-toothed tigers — must have been present in the ecosystem.

Love Dalen, a professor at the Center for Palaeogenetics at Stockholm University who works on mammoth tooth DNA research but was not involved in the work, said the groundbreaking discovery really “pushes the limits” for the field of ancient DNA.

“This is a really great article! It can tell us about the composition of ecosystems at different points in time, which is really important for understanding how past climate changes have impacted biodiversity. This is something animal DNA can’t do.”

“Furthermore, the findings that several temperate species (like their spruce and mastodon relatives) live at such high latitudes are extremely interesting,” he added.

Climate change?

Willerslev said the 16-year work was the longest project of its kind in which he and most of his research team were involved.

Further study of environmental DNA from this period could help scientists understand how various organisms might adapt to climate change.

“It gives us insight into a climate we expect to encounter on Earth due to global warming and how nature will respond to rising temperatures,” he explained.

“If we can read that right, it really holds the key to how organisms can adapt and how we can help organisms adapt to a rapidly changing climate.”