North American Migration
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. Outlines of the two sets of remains are shown at left and center. Also found in the grave were a stone cutting tool, above center, and animal antlers with spear points, right of center. Ben Potter, University of Alaska Fairbanks

How humans arrived and settles in America has always been a topic of debate among archaeologists. The most widlely believed idea is that people migrated from Asia to America during the last ice age through a bridge connecting the two continents.

However, a latest study conducted by researchers at the University of Alaska suggests that people might have travelled up to Alaska and stayed there for a while before moving to America. The study is based on the analysis of the mitochondrial DNA derived from the bones of two infants found buried at an Alaskan campsite.

In a paper published in the Proceedings of the National Academy of Sciences, the researchers say that the infants were buried at the campsite nearly 11,500 years ago. The genetic material isolated from the children, is thus, among the oldest ever DNA found in America.

In addition, the infant DNA is the first ancient genetic material discovered around the region of Bering Strait. It is believed that humans first settled in Beringia before moving to parts of North and South America.

The archaeological site was discovered back in 2010 and an analysis of the region revealed that people visited the same area between 13,200 and 8,000 years. They visited during the summers, stayed in tentlike structures and caught salmon and hares.

In 2011, a team of archaeologists recovered the skeletons of two children from a burial pit. While the first one was an infant, who had died a few months after birth, the other one was probably a late-term fetus.

The researchers were still not sure how the fetus ended up being in the same grave. Therefore, they decided to drill out small pieces of bones from the skeletons and send it to researchers at the University of Utah for further analysis. The bone samples were recovered after taking the proper consent of Native American tribes staying around the area.

The analysis of mitochondrial DNA revealed that the two children had markedly different set of genes, suggesting that they belonged to different mothers. That is, they belonged to two different lineages of Native Americans found somewhere else in America.

The researchers say that the genetic diversity suggests that humans may have stayed in Beringia for about 10,000 years before spreading through the Americas. The study finding supports the “Beringian standstill model” which was put forward by researchers at the University of Illinois in 2007.