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Thanks! I do know that some of the genes are very helpful on their specific pages, but some only have the scientific names and where they are on a chromosome, which of course is spectacularly useful.

New question: what happens when you breed the offspring to a horse without the gene? Does the copy always carry, or does it have a chance of not?

One correction to what Cheers has said.

A horse passes on one of its copies of each of the many color and/or pattern genes to every foal. There is a 50% chance that it will pass each of the two copies of a gene, but that percentage doesn't change based on previous breeding results. It isn't correct to say that half of a horse's foals will get the dominant allele and half will get the recessive.

It's like tossing pennies--each time you flip one into the air there is a 50% chance that it will come down heads and a 50% chance that it will come down tails. But you can toss that penny up 50 times and get a result like 35 heads and 15 tails. Getting a string of 4 heads in a row does not change the odds of getting a head the next time. It is still 50%.

Also, try thinking about the genetic information this way:

Every horse has two copies of the gene for every color and pattern, but only horses which have a copy of allele, the version or form that causes the gene to affect the pigment in the horse's hair, will show that pattern or color in their appearance.

In most cases there are two alleles for each gene, but some genes have more.

There are 4 versions of the agouti (A) gene, which causes black pigment in the mane, tail, and lower legs, in the game (Ammit's best representation of what current genetic science knows about it). These alleles are A, the normal dominant form; A+, the Wild Bay version that produces manes and tails and lower legs that are lighter than A does (This is actually dominant over the A allele.); At, which makes brown horses when it is not paired with a more dominant allele like A or A+; and a, the recessive form which does not affect black pigment at all.

The Kit gene has many, many alleles, many of them homozygous lethal, causing foals to die in utero, depending on where and how badly they break the Kit gene. (The main purpose of the Kit gene is not color production, but breaks in it affect color as well as the vital functions that it controls.) These Kit alleles produce roaning, tobiano spotting, sabino spotting, and the many versions of dominant white, (the homozygous lethal alleles of Kit).

The cream gene has three--C, which does not affect coat color, Ccr which causes palominos, buckskins, etc. when one copy is present and cremellos and perlinos, etc. when two copies are present, and Cprl which causes pearl horses.

If I'd had a little more time this morning, I intended to add that usually it is the dominant allele (capitalized notation) which gives the affect of the gene. However, there are two genes which are expressed only when a horse has two recessive alleles. One is very common--the flaxen gene gives red-based horses (ee aa) a light mane and tale when homozygous recessive (ff). Satin, one of the rare fantasy genes is also expressed when it is homozygous recessive.

Here is a homozygous recessive satin horse so that you can see the affect.


http://hj2.huntandjump.com/horse.php?horseid=93412

It is also important to be aware that frame, Olw, is homozygous lethal, and if you breed two frame carriers together there is a 1 in 4 chance of a dead foal. All dominant whites are homozygous lethal. So are Splash 2 and Splash 3, which are also lethal in combination. Sabino 1 and Sabino 2 are lethal in conjuction with the dominant whites.