The reasons were three fold: 1) the early evidence that HIV was widespread in central Africa; 2) the evidence that HIV was more variable in Africa (hence longer presence); and 3) prior experience with HTLV-1 and HTLV-2 and their related retroviruses in African and Asian primates (STLV strains), especially the evidence suggesting a chimp origin Retroviruses – the family of viruses that includes HIV – are almost half a billion years old, according to new research by scientists at Oxford University. That's several hundred million years older than previously thought and suggests retroviruses have ancient marine origins, having been with their animal hosts through the evolutionary transition from sea to land. The team studied a chicken virus called Rous sarcoma virus that causes cancer in chickens and is similar to HIV. "The question is, how do retroviruses build new virus particles?"asked Leslie Exogenous retroviruses that currently form a health threat to humans intriguingly belong to those absent groups. The best studied of the two infectious human retroviruses is the lentivirus human immunodeficiency virus (HIV) which has an overwhelming influence on its host by infecting cells of the immune system. Solution. The correct option is A DNA is not present any stage in the life cycle of retroviruses. Retroviruses are so named because they contain the enzyme reverse transcriptase or RNA-dependent DNA polymerase (RdRP). The genetic material of these viruses is RNA. From their genetic RNA they produce DNA using RdRP; e.g., Rous sarcoma virus. The diameter of the HERV-K VLPs ranges from 120 nm to 210 nm with a mean diameter of ~173 nm (Fig. 1e), significantly larger than other retroviruses, including HIV-1 and HIV-2, RSV, MLV, HTLV-1 .

is hiv a retrovirus