Among the first humans to arrive in the Americas were people from present-day China. This is the finding contained in a new study conducted by scientists at Kunming University, China, according to which these men arrived in two distinct migrations during and after the last ice age. "Our findings indicate that, in addition to the Native American ancestral sources previously indicated in Siberia, northern coastal China also served as a gene reservoir to contribute to the gene pool," said Yu-Chun Li, one of the report's authors.
Li added that during the second migration, the same lineage settled in Japan, which could help explain the similarities between the arrowheads and prehistoric spears found in the Americas, China and Japan. It was once believed that the ancient Siberians, who crossed an existing land bridge in the Bering Strait that connected present-day Russia to Alaska, were the only ancestors of Native Americans. More recent research, conducted since the late 2000s, has indicated that more diverse sources from Asia may be linked to an ancient lineage responsible for founding populations throughout the Americas, including Bolivia, Brazil, Chile, Ecuador, Mexico, and California.
Known as D4h, this lineage is found in mitochondrial DNA, which is inherited only by mothers and is used to track maternal ancestry. The team at the Kunming Institute of Zoology embarked on a 4-year D10h hunt, sifting through 100,000 modern DNA samples and 15,000 ancient DNA samples across Eurasia, eventually arriving at 216 contemporary and 39 ancient individuals who came from this ancient lineage.