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Post by Sonya on Apr 15, 2012 23:34:40 GMT -5
This is just so you understand the genetics of your horse. If you'd like assistance with your horse feel free to contact the admin or a 'fairy'.
Extension Locus
Horse color genetics is concerned with two basic coat color pigments: phaeomelanin (red)and eumelanin(black). Modifications of these pigments produce the whole spectrum of horse colors that we observe in modern horses. Red pigment is produced by the recessive alleles of the extension locus (designated E).
A horse that is EE or Ee is black, a horse that is ee is chestnut. A chestnut horse will never produce a black foal.
Agouti Locus
The A or Agouti locus controls the distribution of black pigment in horses with at least one E+ allele at the extension locus: whether it occurs evenly throughout the body, as in true black horses, or only in certain parts, as in bays and browns.
A horse with Aa will be Bay. Horses that are AA are black based. Such as a chestnut with AA will be liver chestnut, Palomino with AA is chocolate Palomino, A bay with AA would be red bay. Horses that are Ee and AtA or Ee and AtAt are brown.
Cream Gene
Alleles at the C locus (the cream dilution gene) are responsible for the palomino, buckskin, smoky black, cremello, perlino and smoky cream. The two known alleles are designated C+ and CCr. CCr is semi-dominant and dilutes red to yellow in a single dose and to pale cream in a double dose. Thus horses of genotype C+CCr are either palomino (for a horses with a chestnut base color) or buckskin (for a horses with a brown or bay base color). Horses homozygous for the CCr allele are either cremello (for a horses with a chestnut base color) or perlinos (for a horses with a brown or bay base color). Cream dilution can have a very subtle effect on black pigment and horses with a black base color are diluted to smoky black (C+CCr) or smoky cream (CCrCCr). It can be very difficult to tell if a seemingly black horse carries the CCr dilution allele, and some horses with the CCr allele have been classified as dark bay (Mariat et al, 2003) or liver chestnut. The wild-type C+ allele is effectively recessive since it needs to be homozygous for there to be no dilution of the base color.
Examples:
Ee,Aa,nCr or Ee,AA,nCr= Buckskin
ee,Aa,nCr or ee,AA,nCr = Palomino
EE,Aa,nCr or EE,AA,nCr = Smokey black
Ee,Aa,CrCr or Ee,AA,CrCr = Perlino
ee,Aa,CrCr or ee,AA,CrCr = Cremello
EE,Aa,CrCr or EE,AA,CrCr = Smokey cream
Champagne Gene
The dilute champagne colors have been about for some time, but from the point of view of horse color genetics champagne has only recently been recognised as being distinct.
The champagne color dilution gene exists in two forms: CHC, the Champagne dilution allele is dominant over the wildtype allele CH+. Therefore champagne horses can be either of genotype CHCCHC or CHC CH+. The CHC allele dilutes red to a golden color, and black to a brown or taupe color.
Simple form
Chestnut + Champagne = Gold Champagne
Bay + Champagne = Amber Champagne
Brown + Champagne = Sable Champagne
Black + Champagne = Classic Champagne
Chestnut/bay/black/brown + Cream + Champagne = Ivory Champagne
Dun Gene
The dun dilution affects both black and red pigments, so it’s presence will show up on any color. It is often considered a primitive color because ancestral and wild breeds are predominately or entirely dun. Interestingly, Arabians & Thoroughbreds don’t carry this dilution. Although often incorrectly interchanged for buckskin, this is one of the few dilutions that can almost always be determined by one physical factor, a dorsal stripe.
Bay + Dun = Zebra dun or classic dun
Black + Dun = Grullo or Grulla
Chestnut + Dun = Red Dun
Palomino + Dun = Dunalino
Buckskin + Dun = Dunskin
Perlino + Dun = Perlino Dun
Cremello + Dun = Cremello Dun
Brown + Dun = Wolf Dun/Olive Grullo
Silver gene
The horse Silver dilution gene dilutes black pigment but has no effect on red pigment. The mane and tail are lightened to flaxen or silver gray, and may darken on some horses as they age. A solid black horse with this gene will be chocolate colored with a lightened mane and tail. A bay horse will have the black pigment on the lower legs, mane and tail lightened. Sometimes bay horses with Silver dilution can be mistaken for chestnuts with a flaxen mane and tail. Silver dilution is inherited as a dominant trait. It is known to occur in Rocky Mountain horses and related breeds, Shetland ponies, Icelandic and Morgan horses
nZ = One copy of the altered sequence detected. Black-based horses will be chocolate with flaxen mane and tail. Bay-based horses will have pigment on lower legs lightened and flaxen mane and tail. No effect on chestnut color.
ZZ = Two copies of altered sequence detected. Black-based horses will be chocolate with flaxen mane and tail. Bay-based horses will have pigment on lower legs lightened and flaxen mane and tail. No effect on chestnut color.
Black horses with silver are often called silver black or silver dapple black
Bays are silver bay or silver dapple bay
Patterns
Sabino: nSb or SbSb
Overo: nO or OO(AKA Lethal white overo, no horse has ever survived with OO)
Splash White: nSpl or SplSpl
Tobiano: nT or TT
Tovero: nOnT or nOTT
Appaloosa: nLp or LpLp
Rabicano: nRb or RbRb - A variation of roan
Roan: Rr or RR
IF all else fails. USE THIS
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