A retrovirus is a primitive life form that has no capacity to replicate on its own, as is true of all viruses. The retrovirus injects its RNA into an existing cell, where an enzyme called reverse transcriptase converts viral RNA into DNA, which is then inserted (or spliced) into the host cell’s DNA. Virologists generally believe that retroviruses are harmless, even beneficial, in a symbiotic relationship with humans during three billion years of evolution, providing mobile DNA blocks in the human genome. In fact, many of our genes first entered our genome as retroviruses.13,14 Some 8–10
...more
