Retroviruses

There's always been these what's called retro viruses, a. Because they have arina, which has to turn backwards into d and a, which then incorporates into the genome. Seven to nine per cent of those base pars on nuclear tides are from old retrovaruses that have incorporated itself into your geno. And we don't really know what they potentially could be doing, but we do know there are some examples where they've shown a benefit.