No, I dont mean viruses you get from sexy time. I mean virus sexy time. Viruses having sex, ie, shuffling round their genetic material.
They do it a lot.
HIV-1 sexy time Ive written about before– because HIV-1 is diploid, two copies of the genome are packaged into one virus. There is lots of ‘hopping’ during reverse transcription, so sometimes things dont ‘hop’ perfectly, and the resulting virus is different from both of its ‘parents’. Thats how HIV-1 gets a shitload of its diversity (NOT just error-prone reverse transcription).
So sometimes HIV-1 sexy time leads to subtle polymorphisms:
Sometimes it leads to a gene duplication (or deletion):
And sometimes, if two different kinds of HIV-1 have infected the same cell, a virus can contain two different genomes. When sexy time comes, the resulting baby-virus can be a totally new mixture of its parents:
We call these guys circulating recombinant forms, and they make vaccine design a bitch.
But retroviruses arent the only ones that can has sexy time.
Segmented viruses love genetic reassortment too. Hell, thats how we got ‘SWINE FLU OMFG 2009’– pigs can be infected by both ‘avian’ and ‘human’ influenza viruses (we normally cant be infected by the bird kind, has to do with sugar, not blagging about that).
Because influenzas genome is 8 pieces of RNA, if one piggie cell is dually infected with a bird virus and a human virus, the baby virus can get say, 3 segments from the birdy virus, and 5 segments from the human virus, and be an avian/human chimera. Well in ‘SWINE FLU OMFG 2009’, a >20 year-old avian/pig virus recombined with a >10 year-old human/pig virus to make a brand new avian/human/pig virus (2/1/5 segments, respectively).
The avian/human/pig virus didnt come from one poor pig infected with all three. An avian/human/pig influenza is just a natural side effect of influenza sex.
Viruses have sex. Its a major source of genetic diversity for a lot of viruses, and a major headache for us.