Prehistoric DNA Analysis Reveals European Migration History

A team of international scientists conducted an analysis of 51 genetic samples of ancient humans, who entered the European continent approximately 45,000 years ago and flourished along with the extinct descendants, the Neanderthals, for millennia. The DNA samples were obtained from the 45,000-7,000-years-old bones of the prehistoric humans. This analysis revealed the migration patterns and population turnover during European history, which was primarily determined by the onset and offset of glaciers and ice age.

The DNA samples suggest that at a point in time, all Europeans were the predecessors of early people from Belgium. Furthermore, it was found that the remote ancestors of European community experienced strong evolutionary modifications at the time of the emergence of Ice Age and a couple of thousand years after it. Temperatures in the continent started to rise about 19,000 years ago, which melted the enormous ice sheets, resulting in the migration of the modern-day inhabitants of Spain towards the northern region.

Another group of people started to move towards northern and western regions from the southeastern region of Europe, about 5,000 years after the first migration. The last major ice age reached its crest around 35,000-19,000 years prior to the modern day and eventually came to an end nearly 12,000 years ago.

“The ability to obtain genome-scale data from ancient bones is a new technology that’s only been around for the last five or six years. It’s a new scientific instrument that makes it possible to look at things that have not been looked at before,” said David Reich from the Harvard Medical School.

The researchers investigated only that DNA that displayed a distinguishing error, in which uracil replaces a segment of cytosine. This error is not present in modern chains of genetic codes. Thus, examining DNA only with those errors enabled the researchers to deal only with the almost-pure prehistoric genetic structures.

A report published in Phys.org revealed, “Archeological studies have shown that modern humans swept into Europe about 45,000 years ago and caused the demise of the Neanderthals, indicated by the disappearance of Neanderthal tools in the archaeological record, explained Reich. The researchers also knew that during the Ice Age—a long period of time that ended about 12,000 years ago, with its peak intensity between 25,000 and 19,000 years ago—glaciers covered Scandinavia and northern Europe all the way to northern France. As the ice sheets retreated beginning 19,000 years ago, prehistoric humans spread back into northern Europe.”

The genetic data show that beginning 37,000 years ago, all Europeans come from a single founding population that persisted through the Ice Age, said, Reich. The founding population has some deep branches in different parts of Europe, one of which is represented by a specimen from Belgium. This branch seems to have been displaced in most parts of Europe 33,000 years ago, but around 19,000 years ago, a population related to it re-expanded across Europe, Reich explained. Based on the earliest sample in which this ancestry is observed, it is plausible that this population expanded from the southwest, present-day Spain after the Ice Age peaked.

“In analyzing DNA from the ancient bones – 45,000 to 7,000 years old – of 51 of these prehistoric humans, a team of international scientists found evidence of population turnover and waves of migration during European prehistory, driven by advancing and retreating glaciers. The last ice age peaked between 25,000 and 19,000 years ago, at which time glaciers covered Scandinavia and northern Europe,” according to a news report published by Csmonitor.

This branch of early humans was displaced from most parts of the continent by 33,000 years ago, the researchers say, but then reappeared around 19,000 years ago, as the ice sheet retreated, when their descendants in the Iberian peninsula (modern-day Spain and Portugal) began to spread throughout Europe.

According to a report in Techtimes by James Maynard, “Temperatures began to warm in Europe roughly 19,000 years ago, freeing the continent of widespread ice sheets. As the frozen cover receded, human populations from modern-day Spain migrated toward the north. Approximately 5,000 years after that time, the second group of people began to travel from southeastern Europe into northern and western regions of the continent. These migrants from Greece and Turkey displaced the earlier population.”

Modern humans first entered Europe roughly 45,000 years before the modern age. This migration spelled the end of Neanderthals, which had previously inhabited the continent. All of the ancient Europeans examined in this study exhibited lineages that traced back to a population that lived 37,000 years ago in a region that would later be known as Belgium. This group was later displaced, and a new population arrived in Europe 14,000 years ago, traveling from the east.

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