Humans arrived in the Americas 10,000 years earlier than thought: study

By Mark Waghorn via SWNS

Humans arrived in the Americas up to 26,000 years ago, about 10,000 years earlier than thought, according to new research.

Scientists have unearthed evidence of Ice Age migrations from the coast of northern China.

First author Dr. Yu-Chun Li, a molecular anthropologist at the Chinese Academy of Sciences, Beijing, said: "The Asian ancestry of Native Americans is more complicated than previously indicated.

"In addition to previously described ancestral sources in Siberia, Australo-Melanesia, and Southeast Asia, we show that northern coastal China also contributed to the gene pool of Native Americans."

His team traced a female lineage by analyzing mitochondrial DNA ,passed from mothers to their offspring.

They identified two migration events, the first between 19,500 and 26,000 years ago during the Last Glacial Maximum.

Ice sheet coverage was at its greatest and conditions in northern China were likely uninhabitable.

The second occurred during the subsequent melting period between 19,000 and 11,500 years ago.

It coincided with a rapid increase in populations due to the improved climate, which may have fueled human expansion into other geographical regions.

In both cases, the intrepid travelers probably set dock in America via the Pacific coast rather than by crossing an inland ice-free corridor - which would not have opened at the time.

The researchers also uncovered an unexpected genetic link between Native Americans and Japanese people.

During the deglaciation spell, another group branched out from northern coastal China and went to Japan.

Li said: "We were surprised to find that this ancestral source also contributed to the Japanese gene pool, especially the indigenous Ainus."

They now live mostly on Hokkaido, the northernmost island. But their lands once spanned from northern Honshu, the Japanese mainland, north to Sakhalin and the Kuril Islands, now a disputed part of the Russian Federation.

The Ainu have long been of interest to anthropologists because of their cultural, linguistic and physical identity.

They were the earliest settlers of Hokkaido, but were oppressed and marginalized by Japanese rule for centuries.

It was long assumed Native Americans descended from Siberians who crossed over the Bering Strait's temporary land bridge.

But the study in Cell Reports adds to a growing body of recent genetic, geological and archaeological evidence that multiple waves of humans journeyed to the Americas from various parts of Eurasia.

It links East Asian Paleolithic populations to founding groups in Chile, Peru, Bolivia, Brazil, Ecuador, Mexico and California.

The researchers scoured over 115,000 DNA samples from across Eurasia to eventually identify 216 contemporary and 39 ancient individuals belonging to the rare lineage.

Comparing accumulated mutations, geographic locations and carbon-dated age of each enabled them to map a branching path.

The discovery helps explain archeological similarities between the Paleolithic peoples of China, Japan and the Americas.

Specifically, the three regions share primitive technologies for crafting arrowheads and spears.

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

The results were backed by an analysis of Y chromosomal DNA suggesting male ancestors of Native Americans also lived in northern China at around the same time as these females. They fill another piece of the Native American jigsaw puzzle.

Kong added: "The origins of several founder groups are still elusive or controversial. Next, we plan to collect and investigate more Eurasian lineages to obtain a more complete picture on the origin of Native Americans."