A story about ancient DNA: Greenland's lost world
In recent years, there has been a lot of progress in the extraction of ancient DNA. Extracting DNA from ancient specimen is not evident due to its degradation over time and, once extracted, databases to assign the taxonomy to these sequences are rather limited. However, due to evolving techniques and an increased interest in the scientific community, big leaps are now being made.
Recently, researchers of the Lundbeck Foundation GeoGenetics Centre in Copenhagen, Denmark extracted DNA from sediment cores sampled in an Arctic Ocean fjord at the Peary Land peninsula, Greenland and they were able to reconstruct an amazing and unexpected world of different animals, plants and even microorganisms. They found traces of mastodon DNA, an extinct species belonging to the genus Mammut. According to the lead scientist of this project this was truly surprising because it is the first record of this animal in Greenland. This shows the power of aDNA, in my opinion, because there has never been any trace in the fossil records of such an enormous animal and yet, it was recovered with degraded DNA that has been sitting in these sediments deep in the fjords for millions of years.
Kap Kobenhavn formation in northernmost Greenland two million years ago reconstructed by Beth Zaiken. Undated handout image obtained by Reuters. (Handout via Reuters)
Next to the broad scala of identified microscopic to macro creatures, this study is indeed also unique because of the age of the identified DNA. The age was pinpointed at up to 2 million years ago, constituting the oldest DNA recovered so far. Up until now the oldest DNA ever extracted was obtained from a molar of a mammoth and was dated up to 1.2 million years ago. An important reason why it is possible to extract DNA of such great age from these sediments is due to the favourable conditions it was preserved in. In colder climates the degradation of DNA is slower, making the permafrost an ideal environment for DNA preservation.
Ancient DNA can give us a glimpse in the past in way that the fossil record cannot and this astonishing study makes me wonder what more we will learn about our past in the following years. But I am not the only one fascinated by this topic, Svante Pääbo, a Swedish geneticist and director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, was awarded the 2022 Nobel Prize in Physiology or Medicine for his ground breaking and pioneering work for which he extracts ancient DNA from bones with a particular interest in the Neanderthals.
Want to read more about Greenland’s lost world, check out this newspaper article of the Arctic today or directly read the words of the scientists in their Nature publication. Interested in the work of Svante Pääbo? Have a look at this profile written by PNAS or his staff page.