A team of scientists from McMaster University, the University of Alberta, as well as the Government of Yukon and the American Museum of Natural History looked at DNA from local soil samples. of the Klondike, Yukon, to study thousands of years of natural history.
gram, which is very little sediment – we can reconstruct the whole ecosystem with a variety of animals that existed in the area “,” text “:” Just by collecting tiny particles of soil – in this case between 0.5 and 1gram, which is very little sediment – we can reconstruct the whole ecosystem with a variety of animals that existed in the area “}}”>Just by collecting tiny particles of soil – in this case between 0.5 and 1 gram, which is very little sediment – we can replenish the entire ecosystem with a variety of animals that existed in the area.says Tyler Murchie, postdoctoral researcher at McMaster University and lead author of the study.
The team was particularly interested in the transition between the Pleistocene and the Holocene, an unstable period of around 11,000 to 14,000 years ago, when large animals such as mammoths, mastodons and toothed cats sabers have disappeared.
The study, published in the journal Nature Communications, concludes that North American mammoth and horse populations were in sharp decline prior to this period. On the other hand, they would not have disappeared 13,000 years ago as suggested by bone archives studied in the past, given that DNA shows that they were still present 6,000 years ago.
This means that in the Yukon, mammoths are said to have become extinct during the present geological epoch, the Holocene, which began about 11,000 years ago. As the latter disappeared from the region, human civilizations were emerging around the world and the first cities were developing.
Archives extracted from permafrost
DNA preserves well in permafrost because it is a cold environment in which there is very little damage from liquid water, oxygen or the sun, says Murchie. Using DNA capture and enrichment technology developed at McMaster University, scientists extracted DNA stored in soil to find out when species appeared and when they died. of the region.
” These fragments are imprisoned until someone comes to collect them. “
During the period studied, the environment of the Yukon changed from the rich grasslands known as
mammoth steppes to the thick boreal forests that we know today. According to the researcher, one of the theories is that the disappearance of large grazing animals has dealt a major blow to plant life.
Part of this theory asserts that much of the northern hemisphere resembled the modern African savannah. When many large animals began to disappear, these types of ecological networks began to fall apart., he explains.
Mr Murchie believes it could be early proof of the impact of human life on ecosystems. Scientists cannot agree, however, whether it is humans, the warmer climate, or a combination of the two that is causing the extinction of large animals like the mammoth.
He believes that reconstructing ancient ecosystems could help answer this question, as well as other debates raging in the scientific world.years “,” text “:” for at least 270 years “}} ‘>for at least 270 years.
Ross MacPhee, who works for the American Museum of Natural History and co-authored the study, believes the study provides new evidence that horses originated in North America.
” Even though mammoths are gone forever, horses are not, since those who lived in the Yukon 5,000 years ago have a direct connection to the species that exist today. “
However, this research could be limited in time. As the Earth warms, permafrost is melting rapidly in the Arctic, making it urgent to collect DNA samples that can reveal the secrets of Earth’s natural history.
If we don’t get the samples back, and they melt and degrade, then we’re going to lose this whole life story that’s been preserved all this time.
With information from Sebastian Leck