Color and Genetics Question

I bred my sorrel mare, Scamperwoods Vixen (Penny), to a buckskin stud and we are expecting a foal next year, early March. I would love to get a buckskin foal out of the mix, or at least a dilute, but I'll be happy with a healthy foal regardless of the color! Today, I found out with research that Penny's dam, Bertas Poca Bunda, is a buckskin. Penny's sire, Scamperwood, is a bay. Would the fact that Penny's dam is a buckskin give a bigger chance of her foal being a buckskin? Does agouti play a part in the chances of buckskin? I would love to learn more about color genetics in detail :)

Here is a good color calculator that you can use to see the probabilities.

Color Calculator

Without knowing anything about the horses' genes, here are your chances, from the site PaintHorseMares posted:

29.17% - Buckskin
29.17% - Bay
16.67% - Palomino
16.67% - Chestnut
4.17% - Smoky Black
4.17% - Black



If the sire is a red carrier, that brings down your chances of bay or buckskin and brings up your chances of palomino or chestnut:

25.00% - Palomino
25.00% - Chestnut
21.88% - Buckskin
21.88% - Bay
3.13% - Smoky Black
3.13% - Black



If he's homozygous black, that eliminates the chance of getting a palomino or a chestnut and leaves you with this:

43.75% - Buckskin
43.75% - Bay
6.25% - Smoky Black
6.25% - Black



If your mare is homozygous for Agouti (which is quite possible, since both her parents have at least one Agouti gene) these become your options:

33.34% - Buckskin
33.34% - Bay
16.67% - Palomino
16.67% - Chestnut





That's about all I can tell you. If you have any information about the stud's parents, or the colors of any foals that either of these horses have previously sired/foaled, that would help. If you have information about previous foals, I also need to know the color of the other parent. If you don't know anything more, I would just pray that he's homozygous for black and that your mare is homozygous for Agouti. That'll give you a 50/50 shot at buckskin or bay, which is your best shot at getting a buckskin.

Hope that helps! : ]

Awesome thanks so much for the help! I have used the color calculator but couldn't narrow down the search because neither the stud or my mare have been tested for anything for colors. The studs sire is a buckskin and his dam is a bay. Neither the stud nor my mare have very many sorrels in their lines, besides my mare being a sorrel herself of course. So if my mare were tested for agouti and the stud for being homozygous black, it could narrow down the choices by a lot? I have seen the word agouti countless times but still don't know what it is xP

ETA: Because the stud doesn't have red based parents does that mean he isn't a red carrier? And also, my mare is maiden and this will be the studs first foal.

Well... the stud's parents don't help much. Finding out if horses are red carriers is nearly impossible without DNA testing them because both bays and blacks can carry red as a recessive gene. His parents aren't red-based, but they can still be red carriers, and if he got a red gene from one of them he could still be a carrier.

Basically, there are three base colors - black, bay, and chestnut. (There's also brown, but I'm going to ignore it for this purpose.) Bay is black with agouti (which restricts the black to the points and lightens the rest).


Assuming these horses are bred to the same color...

- Bays can produce bays, blacks, and chestnuts. You have to find out if they are heterozygous or homozygous for agouti and whether they are heterozygous black (aka a red carrier) or homozygous black - if you want to narrow down the options.

- Chestnuts can only produce chestnuts. Although they can carry the agouti gene, it can only be expressed if they're bred to a black or bay-based horse (like your mare is).

- Blacks can only produce blacks and chestnuts (because if they carried agouti, they would be bay - not black). They can either be homozygous black (EE), or heterozygous black (Ee). If they're EE, they can only produce black horses. If they're Ee, they can produce black or chestnut.






If you tested the mare for agouti and the stud for black, it would narrow down the options only if they both tested homozygous. You can only get bay or buckskin then... Since he's homozygous black, the foal will be black-based - but since she's homozygous agouti, the foal will be bay-based. Then it's just a 50/50 shot at whether the foal gets the cream gene from the stud.

Okay that makes sense.. Let's just hope for a buckskin filly but if not, it's not a big deal Thanks so much for the help!

No problem : ]

Is their any testing that can determine if the stud will pass on the cream gene to the foal?

Nope. The only way you can know for sure is if he's homozygous (cremello, perlino, or smoky cream), but even then you only know for sure that he'll pass on one cream gene. You still don't know if he'll pass on one or both.

Ah that's a bummer... I'd love it if the only two possibilities were palomino and buckskin (if my mare is homozygous for agouti..)