[katylynn06]

Sorrel mare was bred to possibly a Red Roan what color do you think the foal will be?

Or

Sorrel mare was bred to a Overo (sp) Paint what color do you think the foal will be?

Is one color more dominant than another?

[JBandRio]

Originally Posted by katylynn06

Sorrel mare was bred to possibly a Red Roan what color do you think the foal will be?

sorrel or red roan, 50/50 chance of each

Sorrel mare was bred to a Overo (sp) Paint what color do you think the foal will be?

You left out the color of the Paint If the Paint is also sorrel, then you will get a sorrel foal. If the Paint is black or bay, then if it is heterozygous for black, then 50% chance of sorrel and 50% chance of black or bay. If the Paint is not sorrel, and is homozygous for black, then you'd get either black or bay.

In any case, there is at least a 50% chance of having a pinto pattern, depending on which ones and how many the Paint actually has.

Is one color more dominant than another?

Horses are either red-based, or black based. The base color gene basically says "black" or "not black", with "not black" being red.

Black is dominant, red is recessive.

If there are 2 red genes, the horse will be chestnut/sorrel based.
If there is 1 red and 1 black, or 2 black genes, the horse will be black based.

Whether or not the black based horse is black or bay depends on the existence or not of the bay modifier. Black horses have no bay modifer, as that modifier limits the black hairs to the points (mane, tail, lower legs). So if bay is present in a black based horse, he will be bay. If there is no bay modifer, he's black.

Those are the very basics of the colors and dominance. Black trumps red, but bay trumps black.

A tricky thing is that a red horse can also have bay, but since, as I mentioned, bay only affects black hairs, and reds don't have any black, you would never know. There are 2 ways to know - either you test for it, or you breed to a black horse who is also homozyous for black, meaning he carries no bay (or he'd be bay) and he cannot pass a red gene to produce a red foal. If you get a bay foal (out of enough foals), then you know the red horse carries bay.

Beyond that, you get into things like gray (when present, always covers up whatever color the horse really is), and the dilute genes (when present, always modifies the base color into things like buckskin and palomino, and the presence of 2 dilute genes makes even more of a modification), the dun gene (when present, always modifies the base color, but the presence of 2 of them doesn't further modify the color) and other cool colors.

Totally separate, which is what many people don't realize, are the patterns - pinto patterns (there are 4), appaloosa patterns (quite a few of those), and many other factors that determine what "color" a horse looks like.

[prettyqtrs]

I think JBandRio covered everything. As always, great post!

[miz fit]

my guess, sorrel x roan, not knowing the colors of either parrent, chestnut foal.

my guess, sorrel x overo, depends on the color of the overo, and if he was homozygous or not assuming the overo is the stud. your guess is as good as mine, not nearly enough info..id guess a zebra?

[lacy]

Wow JB, nice post!

[Dawn]

Would the cross to an overo not only be a 25% chance of a coloured foal? With a possibility of 50% chance (if homozygous)?

Or did I flunk out of genetics?

[JBandRio]

LOL, no, you didn't flunk. If you have 1 pinto parent, there is at least a 50/50 chance of passing on a pinto gene. Since Overos are often 2 patterns, usually Frame and Sabino, sometimes Frame and Tobiano, sometimes Splash thrown in there, etc. and since the Overo patterns are only ever heterozygous for Frame, possibly homozygous for Sabino, not sure about Splash, and since Tobi can also be homozygous, each pattern has at least a 50/50 chance of being passed on. If there is more than one pattern, then the odds start going up from there that at least 1 will be passed on.

[miz fit]

i know of a homozygous stallion that throws color no matter if he is bred to a solid or a colored mare. I have found that to be true with homozygous stallions

[Dawn]

Oh wait, I guess I did flunk!

Never was my best subject anyway.

[JBandRio]

Originally Posted by miz fit

i know of a homozygous stallion that throws color no matter if he is bred to a solid or a colored mare. I have found that to be true with homozygous stallions

That's the definition of homozygous - that trait WILL be passed on If it's a dominant trait, it will always show up. Well, I shouldn't say always, as some traits are incomplete dominant, meaning they are there, but not necessarily expressed.

Dawn, you didn't flunk genetics, just math