MOLECULAR PHYLOGENY OF HUMAN T-CELL LEUKEMIA-VIRUS TYPE-I AND TYPE-IIOF AMERINDIANS IN COLOMBIA AND CHILE

Six human T-cell leukemia virus type I (HTLV-I) and eight human T-cell leukemia virus type II (HTLV-LI) cases newly isolated from the South American countries of Colombia and Chile were analyzed together with t he two Amerindian HTLV-I isolates previously reported. All of the HTLV -I isolates belonged to the transcontinental subgroup of the ''cosmopo litan'' group, and Colombian isolates, including those from native Ame rindians and Negroes, formed a single tight cluster within this subgro up. The transcontinental subgroup consisted of isolates from various r egions such as the Caribbean basin, India, Iran, South Africa, Sakhali n, and Japan, and included isolates from the ''Ainu'' and ''Okinawa'' people, regarded as relatively pure Japanese descended from the prehis toric ''Jomon'' period which began more than 10,000 years ago. This im plied a dis semination of the subgroup associated with the movement of human beings in ancient times. On the other hand, all of the HTLV-II isolates from native Amerindians in Colombia and Chile belonged to the HTLV-IIb subtype which has previously been reported to be mainly ende mic in certain populations of native Amerindians. The southernmost iso late from Chile, showing wide distribution of the IIb subtype in nativ e South Amerindians and largest heterogeneity of the subtype in Colomb ian isolates, supported the idea that the HTLV-IIb subtype has been en demic for a long time in native Indians of South America.