A new DNA recovery technique has been developed by a team of researchers from McMaster University, making it possible to pull the genomes of plants and animals, many of which have been long extinct, from less than a gram of sediment.

This newest DNA extraction method allows scientists to reconstruct the most advanced picture so far of the ancient world.

Permafrost samples from four sites in the Yukon, which represent different points in the Pleistocene-Holocene period, approximately 11,000 years ago, were analyzed by researchers. During this period, the extinction of a large number of species, such as mastodons, mammoths, and ground sloths, occurred.

From the analysis done on the DNA samples, surprising new information was uncovered about the way the events leading to the extinction unfolded. One of the things the team discovered was that the woolly mammoth actually survived far longer than originally thought.

The team was also able to find the genetic remnants of different animal species, including mammoths, reindeer, bison, and horses, as well as thousands of plant varieties. These remnants were pulled from as little as 0.2 grams of sediment.

The researchers determined that woolly mammoths and horses likely survived in the Yukon’s Klondike region until as recently as 9,700 years ago. This is thousands of years later than the previous estimates from research done on fossilized remains.

This new technique has resolved a longstanding problem for many scientists who need to separate DNA profiles from substances mixed in with sediment. Before, the process required harsh treatments that destroy much of the usable DNA, but using the new DNA extraction strategy, the team was able to demonstrate that it is possible to preserve much more DNA.

According to Hendrik Poinar, evolutionary geneticist, director of the McMaster Ancient DNA Centre, and lead author of the study, this revolutionary method that allows researchers to pull the DNA of extinct animals and plants from a few grams of soil enables a new kind of work to help us uncover the frozen past.

He added that the research also paves way to maximize DNA retention and improve our understanding of change through time. This includes climate events and human migration patterns as well as events with no preserved remains.

Tyler Murchie, another lead author of the study and a Ph.D. candidate in the Department of Anthropology, said that even though organisms, like humans, shed cells throughout their entire lives, causing much of the genetic material to quickly degrade, a small fraction is safeguarded for millenia through sedimentary mineral binding.

Through the new DNA extraction method, remarkable research can be done in order to uncover the diversity of environmental DNA by sampling very small amounts of sediment — even without the presence of surviving biological tissues.

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