All Populations on the Largest Continent Share a Common DNA Thread—Except for One

Scientists investigating Denisovan ancestry in East Asian populations have uncovered a striking exception: the Jomon people of ancient Japan. Unlike nearly all other groups in the region, the Jomon exhibited minimal to no Denisovan DNA, setting them apart from other East Asian lineages.

The study, recently published in Current Biology, reveals that the Jomon were the only East Asian group lacking significant Denisovan genetic contributions, a discovery that puzzled researchers. Typically, Denisovan ancestry is widespread across Eurasian populations, yet it appears to have largely bypassed the Jomon.

Researchers suggest two potential explanations for this anomaly. One possibility is that the Jomon descended from a distinct ancestral lineage that initially did not intermix with Denisovan-influenced populations. Alternatively, Denisovan DNA may have been incorporated into East Asian populations after the Jomon lineage had already become established, leaving them largely unaffected.

By analyzing ancient genomes from across Eurasia, scientists observed that many East Asian groups share Denisovan DNA segments from a common episode of interbreeding. In contrast, the Jomon lacked these markers despite originating from the same broader East Asian ancestral population. This indicates that gene flow occurred from populations with little or no Denisovan ancestry, effectively diluting Denisovan genetic influence in early Japanese populations.

This suggests that modern humans entered East Asia through different dispersal routes and that Denisovans were not evenly distributed across the region, the studys authors note. The team emphasizes that Denisovan DNA serves as a valuable tool for tracing ancient population movements and understanding human evolutionary history.

Overall, the findings highlight the Jomon people as a rare exception among East Asians, providing a unique window into the complex genetic landscape of ancient Eurasia.

Author: Aiden Foster