By sequencing the mitochondrial genomes of almost 100 pre-Columbian South American skeletons and mummies, between 500- and 8,600-years-old, an international science team has confirmed that the arrival of Europeans in the region had a devastating impact on the indigenous population’s genetic diversity.
“This dataset provides a genetic view of the possible role played by European colonization in reducing the overall Native American genetic diversity to the low levels observed today,” the researchers wrote in their study published in Science Advances over the weekend.
In the study, the researchers sequenced the mitochondrial genomes of 92 ancient humans. Interestingly, they found that none of the genetic lineages were present in modern-day populations.
“The only scenario that fit our observations was that shortly after the initial colonization, populations were established that subsequently stayed geographically isolated from one another, and that a major portion of these populations later became extinct following European contact,” said lead author Bastien Llamas, of the University of Adelaide’s Australian Centre for Ancient DNA, in a statement.
The general consensus is that the arrival of Europeans in the Americas coincided with a substantial drop in the Native American population. According to the Christian Science Monitor, estimations of the die off range between 50 and 90 percent of the population.
The research also sheds light on the initial migration to the Americas at the end of the Pleistocene.
“Geographically widespread signals of low diversity and shared ancestry—particularly striking in maternally inherited mitochondrial and paternally inherited Y-chromosome sequence data—suggest that small founding groups possibly initially entered the Americas in a single migration event that gave rise to most of the ancestry of Native Americans today,” the researchers wrote.
Alan Cooper, of the Australian Centre for Ancient DNA, said the study’s genetic reconstruction confirms that the first people entered America around 16,000 years ago via the Pacific coast. From there, they spread southward. Archaeological evidence from Chile shows that humans were in the area around 14,600 years ago.
“Our study is the first real-time genetic record of these key questions regarding the timing and process of the peopling of the Americas,” said study author Wolfgang Haak, of the Max Planck Institute for the Science of Human History, in a statement. “To get an even fuller picture, however, we will need a concerted effort to build a comprehensive dataset from the DNA of people alive today and their pre-Columbian ancestors, to further compare ancient and modern diversity.”
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