We now have the complete pig (aka Sus scrofa) genome! You know what that means……….!!!
While I am a huge fan of all ERVs, including PERVs, PERVs hold a special place in my heart.
Physicians can use pig parts and organs for human transplants. Thanks to a pig, someone I love very much is alive today. It would be fantastic if pigs could be used to their full medical potential… but because of PERVs, some people who could benefit from a pig transplant, cannot.
Pigs have ERVs just like humans do. And some of their ERVs are relatively young, which means they have not entirely deteriorated yet, which means they might be able to code for a functional retrovirus.
Take someone who is sick, give them a pig organ, put them on immunosuppressive drugs… what if a PERV pops up? What if we get a new human retrovirus? What if we get a pig version of HIV? A trail of suffering and death, when all we wanted to do was save some lives.
Well, that has been studied, extensively, and we think it is safe. Clinical trials are going on around the world trying to help people with pig parts, and everyone is doing okay– No PERVs.
But now that we have the entire pig genome sequenced, scientists have a lot more data to mine to see if there are any PERVs hiding behind piles of junk DNA. In fact, there are. These folks found 175 previously undescribed PERVs. Happily, they only found about 20 gamma-ERVs, and 4-beta-ERVs, that would have a shot in hell of doing anything– They were almost complete. But none of them were complete. They all had deletions/mutations/mistakes in either gag, pol, or env, rendering them defective.
Unfortunately, we know from the XMRV fiasco that given the right conditions, fractured ERVs can create an infectious agent.
Happily, again, there is a lot of polymorphism between pigs and these ERV loci. If we study the almost-intact guys, figure out which ones are most likely to cause trouble, we could try to find pig lines that lacked one/the other/both/all of the trouble-makers.
We need options for our organ transplants, but aint nobody want a PERV inside of them.