日本に分布するHTLV-1株からみた生物系統地理学

We conducted phylogenetic analyses and an estimation of coalescence times for East Asian strains of HTLV-1. Phylogenetic analyses showed that the following three lineages exist in Japan: “JPN”, primarily comprising Japanese isolates; “EAS”, comprising Japanese and two Chinese isolates, of which one originated from Chengdu and the other from Fujian; and “GLB1”, comprising isolates from various locations worldwide, including a few Japanese isolates. It was estimated that the JPN and EAS lineages originated as independent lineages approximately 3,900 and 6,000 years ago, respectively. Based on archaeological findings, the “Out of Sunda” hypothesis was recently proposed to clarify the source of the Jomon (early neolithic) cultures of Japan. According to this hypothesis, it is suggested that the arrival of neolithic people in Japan began approximately 10,000 years ago, with a second wave of immigrants arriving between 6,000 and 4,000 years ago, peaking at around 4,000 years ago. Estimated coalescence times of the EAS and JPN lineages place the origins of these lineages within this 6,000-4,000 year period, suggesting that HTLV-1 was introduced to Japan by neolithic immigrants, not Paleo-Mongoloids. Moreover, our data suggest that the other minor lineage, GLB1, may have been introduced to Japan by Africans accompanying European traders several centuries ago, during or after “The Age of Discovery.” Thus, the results of this study greatly increase our understanding of the origins and current distribution of HTLV-1 lineages in Japan and provide further insights into the ethno-epidemiology of HTLV-1.長崎大学学位論文 学位記番号:博(医歯薬)甲第839号 学位授与年月日:平成28年3月9日Author: Masashi Otani, Katsuyuki Eguchi, Tatsuki Ichikawa, Kohei Takenaka Takano, Toshiki Watanabe, Kazunari Yamaguchi, Kazuhiko Nakao, Taro YamamotoCitation: Tropical Medicine and Health, 40(4), pp.117-124; 2012Nagasaki University (長崎大学)課程博