Grey gene?

JaiteraMiniatures · May 10, 2010

Okay, so in order for a horse to be grey they only need one dominant allele? They can be heterozygous for grey OR homozygous, but both will visually be grey? What other dominant colors are there? Aren't black and chestnut also dominant...is bay one black and one red gene? Do only bays carry agouti?

I like genetics, they're just a little bit confusing

...is there a good website or book out there that helped you guys understand it all better?

Oh, and I've always wondered what causes palomino...our mare is a palomino; sire is buckskin, dam bay. What did she receive from each parent to become a palomino?

Hopefully that wasn't asking too much of you guys

It all fascinates me.

Horse Feathers · May 10, 2010

Try this web site

http://www.animalgenetics.us/CCalculator1.asp

love_casper · May 10, 2010

Grey is dominant, zygosity doesn't affect appearance. It's dominant over every other color, and once greyed out usually you can't always tell what color the horse originally was. The only time you ever wouldn't be able to see grey on a mature horse would be if it was... say... maximum pinto or something, where all the skin would be pink anyway and you might not see it.

Your other questions... well I'll PM you the link to my half-done color genetics website. I don't want to officially "release" it yet until I have the other like 12 pages of documents on my comp added to it, and a few more pics collected. But I have finished and published all the ones needed to answer your questions.

anyssapark · May 10, 2010

Yes, you are correct. For a grey to be a grey, it must have one dominant allele. So it cant skip a generation. One or both parents must be grey for a foal to be. And it can be homozygous or hetrozygous grey.

Black is dominant also.

Red (chestnut/sorrel) is recessive. It can skip generations. A horse needs TWO copies of the red gene to be red, but it can be a black horse that carries red. Hence why sometimes when we breed to blacks we may get a red foal - as both parents may be red carriers. If a horse doesnt carry red, then its homozygous black.

Agouti (the gene that restricts the black to the points - making a black a bay) is a dominant modifying gene. It cant skip generations, and one parent (atleast ) must carry it. BUT agouti doesnt affect a red based horse - (as it had no black to restrict to the points!!) so you can have a red base horse that carries agouti. So you could get a bay when breeding ablack and a chestnut, if the chestnut carries it.

Cream is another dominant gene. It modifys also. It cannot skip generations, and atleast one parent must carry the gene (BE creme). Cream will turn a chestnut/sorrel in to a palomino, a black into a smokey black, a bay in to a buckskin etc etc. A black based horse that carries TWO creme genes (one from each parent) is a perlino, and a red based horse that carries two cream genes is a cremello. These are homozygous creme and will only ever through dilute foals.

So your palomino is a chestnut/sorrel (both parents carry red) with one copy of the cream gene.

Your mare may carry agouti to throw a buckskin/bay when bred to a black based horse (if one of her parents carry's it) as it wouldnt show up on her. But she cannot carry black. If she carried it, she would BE black based.

Hope that helps some and isnt confusing

The book i love about genetics is call "equine genetics - by dr philip sponenburg" (sp) it is very in depth, but covers everything.

Renee