New genetic evidence indicates Ice Age humans migrated from China to the Americas

Tracing back the origins

According to previous studies, Siberians who entered the region via the Bering Strait were said to be the sole ancestors of Native Americans. However, some recent examinations have indicated that this was not the case and that various other populations could also have ventured into the Americas. 

The authors of this new study used mitochondrial DNA to trace a female genetic lineage (D4h) from northern coastal China to the Americas. The researchers “followed the trail of an ancestral lineage that might link East Asian Paleolithic-age populations to founding populations in Chile, Peru, Bolivia, Brazil, Ecuador, Mexico, and California.” 

This lineage was discovered by analyzing a large pool of genetic data. A total of 100,000 modern and 15,000 ancient DNA samples from Eurasia were examined. About 216 contemporary and 39 ancient individuals’ samples belonged to this rare lineage.

They then compared the mutations, geographic locations, and carbon-dated ages of these individuals to deduce the branching path of the lineage.

Migration during the Ice Age 

This led to the conclusion of two migration events undertaken by the Chinese ancestors — one during and soon after the last Ice Age. 

The lineage radiation suggested that the first migration took place between 19,500 and 26,000 years ago, during the Last Glacial Maximum. This was the period when a thick ice sheet covered parts of what is now northern China. The frigid conditions may have made life difficult for prehistoric humans, so they migrated from the area. The second migration occurred between 19,000 and 11,500 years ago, during the melting period. 

Interestingly, the study also discovered that some people from northern coastal China traveled to Japan during the second migration. This migration would have most likely added to the gene pool of indigenous Ainus in Japan.

This evidence of migration also points to similarities in the design of prehistoric artifacts recovered from the Americas, China, and Japan, such as arrowheads and spears.

“This suggests that the Pleistocene connection among the Americas, China, and Japan was not confined to culture but also to genetics,” said senior author Qing-Peng Kong, an evolutionary geneticist at the Chinese Academy of Sciences.

The new study raises a number of unanswered questions about Native American ancestry. It appears that there is still a lot more to learn about early human migration to connect the missing dots.

The study has been published in the journal Cell Reports.

Study abstract:

Although it is widely recognized that the ancestors of Native Americans (NAs) primarily came from Siberia, the link between mitochondrial DNA (mtDNA) lineage D4h3a (typical of NAs) and D4h3b (found so far only in East China and Thailand) raises the possibility that the ancestral sources for early NAs were more variegated than hypothesized. Here, we analyze 216 contemporary (including 106 newly sequenced) D4h mitogenomes and 39 previously reported ancient D4h data. The results reveal two radiation events of D4h in northern coastal China, one during the Last Glacial Maximum and the other within the last deglaciation, which facilitated the dispersals of D4h sub-branches to different areas including the Americas and the Japanese archipelago. The coastal distributions of the NA (D4h3a) and Japanese lineages (D4h1a and D4h2), in combination with the Paleolithic archaeological similarities among Northern China, the Americas, and Japan, lend support to the coastal dispersal scenario of early NAs.