Re: Fwd: Paint and pinto coloring

[Lynette Helgeson <helgeson@lansford.ndak.net>]

Leigh331@aol.com wrote:
> 
> OK, I've been quiet about this as long as I can. Lets see if I can explain
> this:
> 
> There has to be at least one parent that has the dominant gene in order for
> there to be a paint foal.
> ****For the sake of example: You do not need to have a dominat gene in order
> to get a specific color: Chestnut is recessive, but if both parents "give"
> their recessive chestnut gene, you get a chestnut foal. Recessive genes can be
> very sneaky. I have two chestnut horses that are out of grey parents!  These
> two horses, bred together will never throw a grey foal, even though all four
> grandparents were grey.

First of all lets understand that the expressed allele in a heterozygous
pair is
known as the dominant allele, the unexpressed one as the recessive
allele. 
The presence of a recessive allele may be masked by a dominant allele,
which leads to the expression "hidden recessive." Dominant alleles are
never hidden by their related recessive alleles. 

This is why you have two chestnut horses out of gray parents is because
your gray parents were dominant for gray, but they were also dominant in
Chestnut since they were not gray when they were born. And both colors
were expressed since they were both dominant. Just like me. I was born
brunette and I am turning gray. That means that my children can be born
brunette just like me, but if they do not have the graying gene in their
genes then they will not turn gray too. Your gray parent horses were
born chestnut which was expressed as a dominant gene, they also had the
dominant graying gene, so they lost the ability to keep their color and
their hair turned white. But they did not lose the gene for chestnut and
they passed that gene to their offspring, but they did not pass the
dominant graying allele of the gene, they passed on the recessive
graying allele of the gene. Which means that the graying gene they have
is paired like this "Gg" and the chestnut foals received the recessive
allele or "g" part of the gene. And since the recessive allele is
unexpressed it will not show.
> 
> Sometimes the parent will have the dominate overo gene and it will be hard to
> find evidence that that parent carries the dominant gene, but it has to be
> dominant.
> ****Again, the jury is still out about overo. Some sources say its dominant,
> others say its recessive. It sometimes responds as both.

If you would do more studying on to why the overo gene is considered
dominant you would discover, just like the experts have, that the overo
gene HAS to be dominant. There is no other way. I could get into that
more if you would like.
> 
> So most breeding stock paints are carrying the recessive overo
>  gene and they will never produce a paint foal without being bred to a
>  paint.

> I hope I explained this OK. There are two color genes in each animal. One from
> Mom and one from Dad. If both the genes are the same, the foal in homozygous,
> if they are different, the foal is heterozygous. If the foal is homozygous-
> the color could be recessive or dominant. If the foal is heterozygous- one
> color is dominant over the other, but this heterozygous foal could grow up and
> produce a foal of it's own- this baby could acquire either the dominant or
> recessive gene from its heterozygous parent.  

Yes, but the dominant allele in the gene is the expressed one and the
recessive allele in the gene is the unexpressed one. 

Lynette