Sediment at Greenland’s northernmost point dredged up around the opening of an Arctic Ocean fjord has yielded DNA from animals, plants, and bacteria dating back around 2 million years, the oldest on record.
A wide variety of animal species, comprising mastodons, reindeers, lemmings, or geese, as well as plant species, such as poplars, birches, and thuja trees, and microorganisms, such as bacteria and fungi, were found by the scientists on Wednesday using DNA fragments. DNA is the hereditary material in living creatures that replicates itself and carries the genetic instructions for making copies of the organism.
The mastodon, a close relative of the elephant, lived in North and Central America until its extinction around 10,000 years ago, along with many other huge Ice Age mammals. The new information demonstrates a greater extent of its distribution than was previously thought. The study demonstrated that ancient DNA can survive for far longer than was previously thought when stored in optimal circumstances, in this instance permafrost.
Collecting DNA
To do this, they collected 41 samples of organic-rich silt from five different locations on the Peary Land peninsula, which juts into the Arctic Ocean, then extracted and sequenced the DNA from each one. DNA was isolated from tiny specks in the sedimentary clay and quartz. In total, they named over a hundred different species of flora and fauna.
There had been futile attempts to find DNA in the samples since they were first unearthed in 2006. Over time, advances in ancient DNA extraction techniques have allowed for a breakthrough. A molar from a mammoth in northeastern Siberia dating back up to 1.2 million years and likewise conserved in permafrost conditions, contained the oldest known example of DNA. Homo sapiens appeared on the scene about 300,000 years ago as a point of reference.
Although fossils are the primary source of information on extinct organisms, they have their limitations, especially when it comes to revealing information about genetic links and features. Here, ancient DNA really comes in handy.
