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SALT LAKE CITY — The ancient remains of two infants uncovered in Alaska are related to two lineages of Native Americans, according to a DNA analysis done by researchers at the University of Utah.
The finding is significant because it supports the Beringian standstill model, which suggests that the descendents of Native Americans spent as long as 10,000 years living on the Bering land bridge between Asia and Alaska, according to the university. Dennis O'Rourke, the senior author of a study published Thursday about the research, said the infants are the earliest known human remains in North America.
Since the two babies have different mitochondrial DNA — belonging to the C1b and B2 Native American lineages — researchers said it shows there was genetic diversity among the population before the group moved south.
"It supports the Beringian standstill theory in that if they [the infants] represent a population that descended from the earlier Beringian population, it helps confirm the extent of genetic diversity in that source population," O'Rourke said in a statement. "You don't see any of these lineages that are distinctly Native American in Asia, even Siberia, so there had to be a period of isolation for these distinctive Native American lineages to have evolved away from their Asian ancestors. We believe that was in Beringia."
Researchers said it is rare to find ancient burials of babies. One of the infants appeared to have died as a 30-week pre-term fetus or was stillborn, while the other died when it was between six and 12 weeks old, according to the study.
The two infants had different mothers but were buried together approximately 11,500 years ago, according to researchers. Their remains were discovered at Alaska's ancient Upward Sun River campsite in a residential structure near a hearth in 2013.
"It's not common to find infants buried together that are not related maternally," O'Rourke said. "It raises questions about the social structure and mortuary practices of these early people," including whether the babies had a common father."
The baby with the C1b lineage is related to native peoples found in Arizona and California, including the Pima and Hualapai Indians, according to researchers. They said lineage C1 has also been identified in Bolivia and Puerto Rico.
There are 37 tribes in the Americas that are connected to the B2 lineage, which was found in the second baby. The Yakama, Wishram, Northern Paiute-Shoshoni and Navajo tribes are among those on the list. Many belonging to the Fremont and Anasazi peoples are also of the B2 lineage.
"Studying the DNA of ancient individuals is important in researching how the Western Hemisphere was populated," U. anthropology doctoral student Justin Tackney said in a statement. "Studying the genetics of these infants who died 11,500 years ago in what is now central Alaska helps answer questions of who these people were and how they are related to modern native populations."
The study was published in the journal Proceedings of the National Academy of Sciences.
