A Further Insight into the Origin of Human T-Lymphotropic Virus Type 1 (HTLV-1) in Japan, Based on the Genotyping of ABCC11

Abstract

Our research into the biogeography of HTLV-1 in Ja- pan has led us to the hypothesis that the virus was intro- duced to Japan in the prehistoric era by the Jomon people. Later, in the Yayoi period (ca.300 BC - ca.300 AD), a mass migration of non-carriers (the Yayoi people) reached Japan from northeastern Asia, and these people became dominant by virtue of their proficiency in advanced technologies such as agriculture and iron works (1). As a result, aggregations of HTLV-1 carriers gradually disappeared from central Ja- pan, where today HTLV-1 remains only in remote areas along the coast and adjacent islands. In order to test this hypothesis, we conducted an experimental study which aimed to identify the relationship between HTLV-1 carrier status and the nucleotide substitution 538G↑A (rc 17822931) in ABCC11, a marker of the earwax type, which represents an inherited trait from either the Jomon or Yayoi people. Our results revealed that the proportion of wet ear- wax among HTLV-1 carriers was 28.6% (10/35), whereas that among non-carriers was only 5% (1/20). The differ- ence was statistically significant (Kai square=4.42, p<0.05). This suggests that the HTLV-1 carrier population inherited a genetic trait from the Jomon people and lends support to the theory that it was the Jomon people who brought HTLV-1 into Japan. Although the process of introduction of HTLV-1 to Ja- pan and its establishment there remain hotly disputed, two