Two distinct genotypes (MY-x and MX) of JC virus previously identified in Hokkaido Ainu

Abstract

Genotyping the urinary JC virus (JCV) DNA is a useful means to gain new insights into the origin of ethnic groups. We recently detected thirteen JCV isolates from the Ainu, an indigenous population living on Japan’s northernmost island (Hokkaido). Based on phylogenetic analysis, these isolates were classified into five genotypes: two (MX and MY-x) were first identified in the Ainu, two (EU-a/Arc and EU-c) are prevalent in northeastern Siberians and an Arctic tribe, and one (MY-b) is widespread among Hondo Japanese, i.e. contemporary Japanese excluding the Ainu. Although these findings have several potential implications for the development of the modern Ainu, further studies are required to reach a definite conclusion. In this report, an isolate in a forensic subject whose ethnic origin was Ainu belonged to the MX genotype and two isolates recently identified in South Koreans and grouped as Native American isolates belonged to the MY-x genotype. The present findings suggest that the MX genotype of JCV is unique to the Ainu, whereas MY-x is spread among some Northeast Asian populations.