According to the study’s scientists, they may have found the connection between ancient people in Alaska and in Asia after deciphering the genetic material of the two babies’ mothers.
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“It supports the Beringian standstill theory in that if [the infants] represent a population that descended from the earlier Beringian population, it helps confirm the extent of genetic diversity in that source population”, Professor O’Rourke said.
Scientists use the name Beringia to describe the vast area that linked Siberia and North America during the last Ice Age, from 28,000 to 18,000 years ago.
This type of wide genetic diversity is important because it gives credence to the ‘Beringian standstill model, ‘ which challenges the idea that humans moved right into the Americas across the Beringian land bridge. “The earliest Native Americans came from the Bering land bridge”. One was a 6- to 12-week-old baby, while the other was a preterm fetus, possibly stillborn.
An illustration of an 11,500-year-old grave in central Alaska that contained a rare double burial of two infants dating to 11,500 years ago. They found the infants had different mothers and were the northernmost known kin to two lineages of Native Americans found farther south throughout North and South America.
Both lineages appear in modern Native Americans, but B2 has previously been found only in tribes that now live farther south, such as the Navajo and the Anasazi of the American Southwest.
The site contained the burials of three children; a cremated 3-year-old; a premature baby; and a 6-week-old infant. Multiple lines of evidence show that the infants were buried at the same time, says Ben Potter, an archaeologist at the University of Alaska, Fairbanks, and the leader of the excavations at USR.
The new University of Utah study, published this week in the Proceedings of the National Academy of Sciences, adds a new wrinkle to the settlement of North and South America from travelers across the frozen bridge over the Bering Strait. But a few experts also believe that the bridges, also known as Beringia, also served as a long-term home for the would-be American settlers.
Still, the new study can’t settle the debate about how long people hung out in Beringia, Tackney said. An analysis of their mitochondrial DNA (which is inherited from mothers) showed that the infants were from distinct genetic groups. Both infants coming from different lineages suggests that after arriving in Alaska from Asia, populations spent around 10,000 years there before expanding outwards into the rest of the continent – a theory called the Beringian standstill model.
During the last Ice age, around 25,000 years ago, the earth experienced low sea levels. The genetic diversity between the two USR infants is what “one would expect” from a population that lived for a long time in Beringia.
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One possibility is that the two infants had the same father, even though their mothers could not have been closely related. The researchers working at the digs in Alaska, led by University of Utah anthropologist Dennis O’Rourke, took mitochondrial DNA samples from the two sets of fossils and managed to get 58.7 million sequences from the first one and 55.8 million from the second, the Daily Mail reports.
