Dating htlv - dauphindating com
Retroviruses are RNA viruses that use an enzyme called reverse transcriptase to produce DNA from RNA.The DNA is subsequently incorporated into the host’s genome. Prior to 1979, the isolation of retroviruses was possible only in nonhuman primates; in fact, it was believed that human retroviruses did not exist.
Molecular dating estimates that the ancestor of HTLV-3 is as old as HTLV-1 and HTLV-2, with an inferred divergence time of 36,087 to 54,067 years ago.
Phylogenetic analysis of all gene regions confirms this relationship and shows that HTLV-3 falls within the diversity of STLV-3, suggesting a primate origin.
However, HTLV-3(2026ND) is unique, sharing only 87% to 92% sequence identity with STLV-3.
Human T-cell lymphotropic viruses type 1 (HTLV-1) and type 2 (HTLV-2) are closely related human complex deltaretroviruses.
Infection with HTLV-1 has been linked to the development of adult T-cell leukemia/lymphoma (ATL/ATLL), a clonal aggressive malignancy of CD4 T lymphocytes.
HTLV-1 is associated with adult T-cell leukemia (ATL) and a variety of immune-mediated disorders including the chronic neurological disease termed HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP).
In contrast, HTLV-2 is much less pathogenic with reports of only a few cases of variant hairy cell leukemia and neurological disease associated with infection.
Human T-cell lymphotropic virus (HTLV) was the first human retrovirus discovered.
HTLV belongs to the Retroviridae family in the genus Deltaretrovirus.
HTLV types HTLV-1 and HTLV-2 viruses are the first retroviruses which were discovered.
Both belong to the oncovirus subfamily of retroviruses and can transform human lymphocytes so that they are self-sustaining in vitro.
HTLV-1 and HTLV-2 are highly related complex retroviruses that have been studied intensely for nearly three decades because of their association with neoplasia, neuropathology, and/or their capacity to transform primary human T lymphocytes.