The tax Gene Sequences Form Two Divergent Monophyletic Lineages Corresponding to Types I and II of Simian and Human T-Cell Leukemia/Lymphotropic Viruses
Evolutionary associations of human and simian T-cell leukemia/lymphotropic viruses I and II (HTLV-I/II and STLV-I/II) are inferred from phylogenetic analysis of tax gene sequences. Samples studied consisted of a geographically diverse assemblage of viral strains obtained from 10 human subjects and 20 individuals representing 12 species of nonhuman primates. Sequence analyses identified distinct substitutions, which distinguished between viral types I and II, irrespective of host species. Phylogenetic reconstruction of nucleotide sequences strongly supported two major evolutionary groups corresponding to viral types I and II. With the type I lineage, clusters were composed of strains from multiple host species. A genetically diverse, monophyletic lineage consisting of eight new viral strains from several species of Asian macaques was identified. The second lineage consisted of a monophyletic assemblage of HTLV-II/STLV-II strains from Africa and the New World, including an isolate from a pygmy chimp (Pan paniscus) as an early divergence within the lineage. High levels of genetic variation among strains from Asian STLV-I macaque suggest the virus arose in Asia. Evidence of the origin of the type II virus is less clear, but diversity among HTLV-II variants from a single isolated population of Mbati villagers is suggestive but not proof of an African origin.
Giri, Adriana; Jill Pecon-Slattery; Walid Heneine; Antoine Gessain; Emilia Rivadeneira; Ronald C. Desrosiers; Leon Rosen; Ronald Anthony; Joko Pamungkas; Diah Iskandriati; Allen L. Richards; Vincent Herve; Harold McClure; Stephen J. O'Brien; and Genoveffa Franchini. 1997. "The tax Gene Sequences Form Two Divergent Monophyletic Lineages Corresponding to Types I and II of Simian and Human T-Cell Leukemia/Lymphotropic Viruses." Virology 231, (1): 96-104. http://nsuworks.nova.edu/cnso_bio_facarticles/697