Research using ancient DNA proved that humans could not have been able to traverse through the corridor on the American continent before 12,600 years ago.
The previous theory was that the first Americans crossed from Siberia to Alaska and then they moved south after the last ice age. However, the ice-free corridor might not have been passable by the time the humans were already proven to have settled in America.
The researchers used the analysis of ancient DNA and remains of plants, animals, and pollen and discovered that the route was ready to be traveled 12,600 years ago. The conclusion made scientists turn to other theories of how the fist Americans arrived in the New World.
The present study is important because it uses both traditional data and modern ones, which makes it the first to corroborate the existing evidence with new discoveries, without clashing information or ignoring data.
The historians believe that humans crossed to North America through Beringia, a piece of land connecting Siberia with the continent that later submerged. Upon their arrival, no one really knows how they managed to get to dry land as a significant part of America was under ice.
It was believed that the human’s arrival coincided with the melting of the glaciers, which was supposed to have happened 14,000–15,000 years ago. However, in the last decade, researchers discovered even earlier human settlements.
The paleoecologists from the University of Copenhagen wondered when the corridor was ready to be crossed. The total length of the path is of 1500 kilometers, and the researchers believe that it would have been essential to use a large animal to make the crossing.
The study focused on fossils found in the narrowest part of the corridor, which is supposed to have been the last part to be opened. The scientists collected eDNA that was electrically bonded to sediment particles and analyzed it to find the timeline of the melting.
The results showed that there was hardly any form of life inside the corridor 700 years after the melting. The first ones to appear were the steppe plants, followed by the woolly mammoth, the bison, and the jackrabbits. After another two centuries, the place was filled with forests of aspen and poplar. Then, the moose and the elk arrived.
The region became a boreal forest 11,600 years ago, which does not fit the current data showing evidence that human settlements appeared 15,000 years ago. Moreover, not even the existence of the Clovis people could be explained by this paleoecologist model.
The author of the study suggests that the humans could have taken the coastal route, even though there is not enough evidence to support this theory. Further research on the islands situated on the western coast may offer more information on whether or not the path was used by the first Americans.
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