DNA Analyses and Genetic Origins of the Ainu

The indigenous people of northern Japan call themselves Ainu, meaning human in their language. The Ainu, the indigenous inhabitants of northernmost island of the Japanese archipelago, are ethnic minority population in Japan. They live in the northern regions of Japan, particularly Hokkaido, the Kuril Islands, and the southern part of Sakhalin. Traditionally, Ainu lived a simple life hunting deer and salmon, gathering wild plants for food, performing traditional dances, and playing music. The Ainu generally have unique physical characteristics such as hairiness, wavy hair, and deep-set eyes, broader and bigger noses, which are very different from those of the ordinary Japanese. In particular, most Ainu men can grow thick, full beard, which is a distinctive trait not commonly found among the Japanese population, until it was outlawed by the Japanese government in 1871. As part of their ancestral tradition, Ainu women had the custom of getting tattoos on their arms, hands, and lips. In the Ainu language, they were called Senuiye, and was perceived as a symbol of beauty, a talisman, and an indispensable tool to prepare their body for after death. Among the Ainu, all natural phenomena, including flora, fauna, and even inanimate objects, are believed to have a spiritual essence, and particular animals such as brown bears continue to be honored in ceremony and ritual as spirit deities called Kemui. The Ainu language is an endangered language isolate. It has no known relation to the Japanese language or any other language family, making it a unique linguistic heritage. Traditionally, the Ainu language was primarily an oral language without a writing system, and it was used for communication within the Ainu community for various purposes, including storytelling, rituals, and everyday conversation. Due to a long history of discrimination and assimilation policies in Japan, the number of Ainu speakers has significantly declined over the years, and today, it is estimated that very few fluent speakers of Ainu remain. The formation process of the Ainu population has been discussed for a long time. Conventionally, the Ainu are considered to be direct descendants of the Jomon people, who lived throughout Japan from as early as 13,000 years ago. However, recent study found that the ancestor of the Ainu could have it mixed with the Okhotsk people, who were genetically similar to those of the lower Amur populations, including the Nefk and Olch. Nevertheless, total Jomon ancestry among the Ainu has been estimated at 70 to 80 percent. This is quite a large proportion compared to other Japanese populations such as mainland Japanese and Ryukyuans. On the paternal haplogroup, the vast majority of the Ainu men belong to haplogroup D, M55, the Jomon male lineage, which were distributed only in the Japanese archipelago. It is noteworthy that they retained a large number of Jomon-related haplogroups in both their paternal and maternal gene pools. In 2008, the Japanese government officially recognized the Ainu as an indigenous people of Japan, marking a significant step toward acknowledging and preserving their cultural heritage. Their current daily lives in terms of food, clothing, and housing are almost the same as those of most people in Japan. However, in line with a growing recognition of Ainu's traditional culture and a movement to restore various aspects of it in recent years, some Ainu people are proactively attempting to learn their traditional culture and pass it on to the next generation. Like most of us, these modern Ainu also struggle for survival.