Kev, help me figure out the dilution factors for my Color patterns.
Foundation: Dark Cornish male X Murray McMurray "Cornish Roaster"
All F1 progeny were sexlinked of sorts. All cockerels were white or white leaking red
All F1 pullets were white or the off-white with black splash or speckles
One of the selected 50%DC/50%WCR pullets was bred back to a 50%DC/50%WCR Cockerel.
The 50%DC/50%WCR cockerel was bred to one of my DC hens
Can you figure out by the patterns what the predominant dilution factor may be? There are two different blues. One has no red leak, just cuckoo type blue bars.
added on 5/12/16 Cited from: http://kippenjungle.nl/basisEN.htm
Chickens have 2 kinds of pigment that define their plumage color. These are the black (sometimes darkbrown/chocolate) pigment eumelanine, melanin for short, and the yellow/red pigment pheomelanine. The "groundcolor" of a chicken is pheomelanine. When this is absent it is called "silver" which looks white.
The common silver-gene allows the expression of some red features like salmon breast or red shoulders. In wildtype chickens the groundcolor is yellow to brown, called "gold". By the so called red enhancers this gold can be boosted to a (dark) red color.
For example the mahogany colored Rhode Island Red.
The gold can be diluted to a yellow, cream or lemon color. The groundcolor can thus be silver, gold, red or yellow. Chickens are rarely fully groundcolored. An example being Buff. This color is partly a mystery for the genes that eliminate the last bits of black are unknown. In the chicken calculator you can approach this color by setting it to a columbian like pattern.
Absence of all pigment delivers a white color. Dominant white (Inhibitor I) inhibits mainly black pigment, rendering the pattern white. Recessive white (Colorless c) inhibits both pigmentkinds, but could leak red. Mottled (mo) is a temporary/local inhibition of both pigments, especially at the feathertip. Sometimes larger areas get white. This inhibition, maybe by building up melanin, is followed often by extreme melanin deposits leading to a black band surrounding the white tip. The sexlinked Barring factor (B) inhibits pigmentdepositing from time to time, giving a barred pattern. Factors affecting feathergrowth also affect the sharpness of the barring. In general the barring is rather unsharp, being blue-light grey instead of black and white.
Consensus and Debate about Chicken Eumelanin Diluters:
Best studied eumelanin diluter is Dominant White. Heterozygotes often show a grayish tint of white and speckles of colored feathers. This white is epistatic to all other eumelanin diluters. Phaeomelanin is not greatly affected, at least in 1 dose. In my own experience Dominant White seems to act as a melanizer, expanding the former black patterned areas. This could be interpreted as phaeomelanin inhibition also, the old consensus.
Most common after that is Blue, being the heterozygous form of Splash. This a gray dilution of black that has a nice contrast with the gold and red tints of the chicken's groundcolor, which it does not affect.Blue tends to be uneven, dark edged or speckled with black and can be darkened by melanizers up to flat black. It also tends to get rusty. Splash (homozygous) is similar to heterozygote Dominant White as it can range from pure white to grayish and speckled.
Then came Lavender or self blue, for the other blue tends to be laced in appearance. This is a recessive mutation often associated with bad feather structure. The consensus is that it is epistatic to the other dilutants by the nature of expression mechanism. Truely epistatic would mean however that it would also cover splash or khaki (hence "white?" in table below). This needs to be confirmed either way. Until then the fanciers' consensus is that the whites would not permit to show the lavender tint. This tint is lighter than splash Blue. Other poultry species' lavenders/self blues do not seem to act epistatic to other diluters and contribute in further dilution of the eumelanin. Lavender also dilutes Phaeomelanin (groundcolor) in chickens.
Dominant White mutation has produced a revertant mutation called Smoky. This allele is dominant to Dominant White but recessive to wildtype. It acts against the mechanism of Dominant White rendering a smoky blue color similar to splash Blue. This blue color would be purebreedable like lavender. The mutation is very rare though, so don't worry about your splash Blue chickens.
There is another allele on the Dominant White gene/locus called Dun. It is recessive to Dominant White but (semi-)dominant to the other alleles. Two copies of the allele render a Khaki color, also called Dun Splash for it can be very white. It is also a clean kind of white, no specks. Darkened by melanizers it gives a nice light brownish lavender tint. One copy of the allele gives a chocolate color instead of black. This is a nice even color ranging from brownish gray to near black chocolate color (probably due to melanizers). No black spots like splash Blue can have. Dun is not very common in some continents, as is Chocolate. Both mutations are often missed or seen as off black.
Chocolate is a sex linked recessive mutation with a similar appearance as heterozygous Dun. The chick down seems darker though. In a recent visit to the dutch Serama empire there was a pullet harbouring both Dun and Chocolate. She was a lighter but prominent brown. Sexlinked brown dilution is the most common eumelanin dilution among birds and poultry, but still very rare in chickens.
Phaeomelanin diluters do not dilute eumelanin, although in some buff chicken breeds the tail-black seems affected. These diluters are not identified.
Edited by lpatelski - 5/12/16 at 4:56pm