Arnie got to meet horses for the first time last week 🙂
It was an unexpected event (horsies were out at a neighbors when we went on a walkie), so I didnt get it on film– but I can recreate it:
Arnie: HOLY SHIT MOM! MOOOOOM! MOOOOOOOOOOOM! WHAT ARE THOSE MONSTERS??? OH GOD THEYRE WALKING TOWARDS US!!!! I WILL PROTECT YOU MOMMY!!!!!!
Horses: *SNORT* *unimpressed blink*
Arnie: AAAAAAAAHH IT SNORTED! GOD THEYRE HUGE! I DONT CARE! YOU SHALL NOT PASS, VILE BEASTS!
Me: Arnie, those horses would kick your ass. Literally. Calm yourself.
Horses: *unimpressed blink* *eat grass*
Arnie: Well… maybe Ill just sniff them, then… *sniff*… *gets a little closer* *sniff*… OMG MOMMY THESE ARE MY TWO NEW BEST FRIENDS I DONT EVER WANT TO LEAVE!!!!!! *WAGWAGWAGWAG*
Brown et al found 978 ERV protein coding genes in the horse genome (there might be more, this is just what they could find with the newest methods).
Of the 978, a grand total of one had the necessary gag, pol, env, and LTRs to even theoretically code for a functional retrovirus. Like others found earlier in the mouse genome, this particular maybe-virus is inserted ‘backwards’ relative to the local horse protein coding genes (backwards means there is less of a risk of normal transcription accidentally making retrovirus RNA).
There was one more that had gag, pol, and env, but no LTRs (which I thought was weird).
The rest were a mish-mash of gag, pols, and envs, in various combinations, with or without LTRs.
But I know the question on all of your minds– How, exactly, do these findings support the Creationist Claim that There Is No Junk DNA, all DNA was specially created by the Christian god 6000 years ago, who sent his only son, Jesus Christ, to Earth to die for our sins?
They dont support the Creationist Claim about ERVs and junk DNA at all, of course.
They looked for expression of 842 of the ERVs. They found RNA from 79 (not from the more complete ERVs). About 20 of them were around normal horse genes (again, our genome likes to keep ERVs away from genes). So, even granting the premise that the ERV transcripts that this group did see werent junk RNA, over 90% of horse ERVs are transcriptionally silent junk DNA. Except the authors know that what they did see was mostly junk RNA:
As very few of the ERV loci identified in this study are capable of producing anything resembling a functional protein clearly their expression is not linked to the production of ERV proteins.
Even in horses, ERVs are junk DNA. And thats a Good Thing.