Breeding for Dilute Colors, continued ...
Buckskins that lack linebacks do not carry the dun allele.
They are heterozygous for the cremello allele, and carry one
or two bay alleles. Cremello is partially dominant, meaning it
has a partial effect if heterozygous and much stronger if homozygous.
A single cremello allele only affects red. It turns red to
gold in the body, and red to white in the mane and tail. Two
copies will make a horse a shade of cream (also called crème
or perlino) with blue eyes and pink skin.
Some apparent buckskins owe their appearance to the champagne
or silver dapple alleles. These horses can throw unexpected colors.
A tip off is that their points are not pure black.
A mating between buckskins that are both heterozygous cremello
and homozygous bay has one chance in four of throwing a crème-colored
(cremello) foal, one chance in four of a bay, and one chance
in two of a buckskin. If the parents are not homozygous bays,
the probability of cremello is the same, both buckskin and bay
are less likely, and they might throw a palomino or sorrel.
A problem with getting crème foals is that you cannot
register them with either the American Buckskin Registry Association
or the American Quarter Horse Association.
If you breed a buckskin to a homozygous lineback dun, you
will always get a lineback foal. If the lineback is heterozygous
dun, you have a 50% chance of getting a lineback. Depending upon
the presence of chestnut alleles in the parents, you also could
get buckskin, palomino, lineback palomino (which cannot be registered
as a buckskin or palomino), or sorrel or bay.
You can be almost 100% certain of getting a buckskin if one
parent is homozygous cremello, either parent is homozygous bay
and no more than one parent carries the recessive black allele.
There are genetic tests for the chestnut, recessive black,
and cremello alleles. By ruling out chestnut or recessive black
alleles in a bay or buckskin, you can be certain it is homozygous
bay. The wild card in such a breeding would be a case in which
the cremello horse hides a dominant black allele. Dominant black
is rare, so it is unlikely to create a surprise foal.
American Buckskin Registry Association
P.O. Box 3850
Redding, CA 96049