I need Chev's help again!

[love4horses]

Sorry Chev, but you are just so good at genetics that I believe I can rely on what you say!

We went and visited the studs today! My mother said we'll be breeding Baylee to the Cremello, and Mystery, I am still deciding between the cremello, pally, and the tobiano they just recently put up for stud. I definitely know what I would be getting from the toby because he is homozygous. What would my color chances be with the pally with Mystery?

They said something about she may have a hidden gene somewhere that may cause a dilution in the baby.

They also told us that Baylee (BTW, this is where we originally purchased Baylee almost two years ago) carries the agouti gene.

Any help is always greatly appreciated!

Thank You Chev!

[chev]

The agouti gene is the gene that causes bay - so, yes, Baylee carries agouti. She also has at least one black allele. If she has two copies of agouti she'll always throw bay or chestnut based foals, never black; if she has two copies of both black and agouti she'd only ever throw bay based foals.

Mystery is black, right? The dilute they're on about is the cream gene; the gene responsible for making bays into buckskins, chestnuts into palominos, and all base colours into double dilutes like cremello when they carry two copies. It works like this;

Bay + Cream = Buckskin
Chestnut + Cream = Palomino
Bay + 2 Cream genes = Perlino (look almost exactly like cremellos)
Chestnut + 2 Cream genes = Cremello

None of these horses can ever 'hide' a cream gene. They will always have a dilute coat. But.... cream dilutes mainly red pigment when a horse carries just one copy, not black. A black can carry cream and give very little outward sign they are carrying a dilute gene - hence the theory that Mystery could be hiding a dilute gene.

Black + Cream = Smoky Black
Black + 2 Cream = Smoky Cream

A smoky cream will look like a cremello; for some reason, even though one crem allele doesn't dilute black pigment much at all, two copies will do exactly what it does to any other base colour.

Smoky blacks can be very difficult to identify by sight. Nott, an Icelandic mare belonging to ambatt on here, is a smoky black; but she appears almost brown. Most smoky blacks will have a brown tinge to the coat, or look faded, but there have been examples that really don't show any sign. Often it's possible to work out the likelihood by looking at a horse's pedigree; no cream dilutes in its immediate breeding will mean it doesn't carry cream (but again, smoky blacks will often be registered as black). Or the breed; cream does not exist in Arabians, Dales ponies, Fell ponies for example; so a pony from those breeds or combinations of breeds won't carry cream.

There is a test for cream that would tell you for sure whether Mystery is carrying the dilute. If she is, then you have a 50% chance of a dilute (palomino, buckskin or smoky black, depending on whether the palomino carries agouti), a 25% chance of a double dilute (cremello, perlino or smoky cream) and a 25% chance of a solid colour.

If Mystery doesn't carry cream there's a 50% chance of a dilute (palomino, smoky black or buckskin) and 50% chance of a solid.