Our previous assumptions need to be corrected.
Through an examination of mitochondrial DNA, a new study published in Cell Reports has come up with compelling evidence indicating multiple migrations between the Americas, China, and Japan during the last Ice Age and subsequent melting phase. The researchers focused on tracing a rare Native American founder lineage across continents and centuries, specifically analyzing the transmission of mitochondrial DNA through women.
By leveraging a dataset encompassing 100,000 present-day samples and 15,000 ancient samples, the research team successfully pinpointed 216 individuals from contemporary populations and 39 individuals from ancient populations who exhibited a shared lineage, IFL Science reported. They accomplished this by employing carbon dating techniques and comparing the mutations acquired throughout the lineage’s journey, thereby mapping out its intricate branching trajectories.
“The Asian ancestry of Native Americans is more complicated than previously indicated,” molecular anthropologist at the Chinese Academy of Sciences, Yu-Chun Li, said in a statement. “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.”
According to the research team, the initial migration event, termed as the “radiation event,” occurred approximately between 19,500 and 26,000 years ago. This time frame coincided with unfavorable cold conditions in northern coastal China, which made it unsuitable for human habitation. The second migration event took place from 19,000 to 11,500 years ago, a period marked by global population expansion and exploration amid improved climatic conditions. Intriguingly, contrary to previous hypotheses suggesting migration via the Bering Land Bridge, the team proposes that both ancient human migrations to the Americas occurred along the Pacific coast. This unexpected finding challenges the prevailing notion and offers new insights into the migration routes taken during the last Ice Age.
Through comparative analysis of migration patterns, as well as arrowheads and spears crafted in a similar manner, researchers have proposed that Paleolithic communities in China and Japan embarked on a journey along the northern edge of the Pacific Ocean, ultimately arriving at the northwest coast of North America. This connection led some to speculate that Native Americans could be descendants of Japan’s Jōmon people. However, a recent genetic study has indicated that this hypothesis is unlikely. Instead, the study suggests that the observed similarities between Native Americans and Asian populations may stem from a shared ancestral lineage rather than direct descent from the Jōmon people.
“Importantly, stemmed points were well distributed around the Pacific rim from Japan to South America with close affinities with each other. Recent findings on stemmed projectile points in North America […] show closer affinity to the nonfluted projectile points in Japan than to those in North Asia.
We attribute this similarity in Paleolithic technology, as well as the phylogenetic relationships of D4h sub-lineages in China, the Americas, and Japan, to a probable Pleistocene connection among these regions.”
The research team additionally discovered evidence of migration from northern coastal China to Japan.
“We were surprised to find that this ancestral source also contributed to the Japanese gene pool, especially the Indigenous Ainus,” Li added. “This suggests that the Pleistocene connection among the Americas, China, and Japan was not confined to culture but also to genetics.”
The team intends to delve into further lineages in order to gain a comprehensive understanding of the ancestral origins of Native Americans.