ridecamp@endurance.net: [endurance] color genetics
[endurance] color genetics
MS LOUISE D BURTON (XXDU78A@prodigy.com)
Fri, 05 Apr 1996 10:26:24 EST
To clear up color genetics a little. There are two main color types, Black
and Chestnut. Several other genes play roles in color, among them are
genes that determine the shade of bay (which is on the black gene), and
chestnuts. Chestnut is recessive. Therefore when you breed a chestnut
(bb) to a chestnut (bb) you can only get a chestnut (bb). Blacks/bays can
be homozygous (BB) or carry the chestnut gene (Bb). Grey is a different
gene! The greying gene is dominant and will mask the chestnut/bay gene.
So, breeding a grey to a non grey, the chance of a grey is 50%. The
chances of a grey when breeding two greys is 75%. On rare occassions, the
grey will be homozygous (GG) and can only produce 100% greys.
*Please note that the Arabian registry will not register a grey unless one
parent is grey, and only a chestnut from two chestnut parents*
If you can follow it, THE HORSE, by Evans, Borton, Hintz, and Van Vleck,
has an excellent chapter on color genetics.
For example, my stallion is bbGg. He is grey and carries the chestnut
gene. If crossed with a chestnut, your outcome is 50% grey, 50% chestnut.
Could he throw a bay? Yes, if the dam was bay (Bbgg or BBgg) or even grey
masking bay (BbGg or BBGg).
I hope this clears things up for you. Please don't ask me about QH, Appy,
and Pinto genetics, as that is way too complicated for me!
Louise Burton
The proud new owner of a six hour old GREY straight Russian colt (whose
mother was bbgg!).
(And also an advanced Biology teacher, FREEZING in OK!)