Great DNA discovery rewrites the history of the Japanese.

Scientists from the RIKEN center in Japan analyzed thousands of genomes and found evidence of a third ancestral group that had previously gone unnoticed. This finding challenges the classical theory of dual origin that dominated for decades and suggests that the current Japanese population is more complex than previously thought.

For a long time, it was believed that the Japanese descended mainly from two lineages: the Jomon, ancient hunter-gatherers, and migrants from continental East Asia who brought rice agriculture. However, the new study with complete genome sequencing of over 3,200 people from various regions of the country reveals a different picture.

The researchers detected clear genetic signals of a third ancestor linked to Northeast Asia and, in particular, to the ancient Emishi of northeastern Japan. This component is more concentrated in the north and decreases towards the west of the archipelago.

Marked regional differences

The analysis showed interesting variations according to geography. In Okinawa, Jomon heritage reaches 28.5% of the samples, while in western Japan it drops to 13.4%. In contrast, the west shows a greater genetic connection with Han Chinese populations, consistent with the significant migrations that occurred between the years 250 and 794 of our era.

These migratory waves coincided with the arrival of government systems, writing, and education in the Chinese style. The Emishi-related component, for its part, remains stronger in the northeast. The results strengthen the idea of a tripartite origin that previous studies of ancient DNA had already suggested.

In addition to population history, the study found genetic material inherited from Neanderthals and Denisovans, archaic groups that interbred with modern humans tens of thousands of years ago. They identified 44 regions of archaic DNA still present in the current Japanese population, several exclusive to East Asians.

Impact on current health

A variant derived from Denisovans within the NKX6-1 gene is associated with type 2 diabetes and could influence the response to treatments such as semaglutide. They also found 11 segments of Neanderthal origin linked to diseases such as coronary artery disease, prostate cancer, and rheumatoid arthritis.

The researchers built a large database called JEWEL that combines genetic information with clinical histories. This allowed them to identify rare variants and loss of function in specific genes of the Japanese population, such as PTPRD (related to hypertension and heart attack) and others associated with hearing loss and chronic liver disease.

Chikashi Terao, the leader of the study, emphasized that the Japanese population is not as genetically homogeneous as previously thought. The analysis allowed for detailed mapping of the population structure according to geographic location.

They used complete genome sequencing, which provides thousands of times more information than traditional methods. This was key to detecting rare variants that help trace ancient migrations and lost populations.

Towards more precise medicine

The work is part of a larger effort to expand genomic studies beyond European populations, which have dominated databases until now. Understanding the genetic particularities of the Japanese can improve the diagnosis and treatment of diseases in Asia.

The findings not only rewrite part of Japan's history but also open doors to personalized medicine that takes population differences into account. The team hopes to continue expanding this genomic library to directly benefit the health of the population.

In this way, a massive DNA study confirms that Japan has a richer and more multifaceted settlement history, with at least three major ancestral components that mixed over the centuries to shape the current diversity of the country.