Why do you get different colors when pairing same colored silkies?

[Sonoran Silkies]

Please, for blue use Bl. B is barring.

Blue is a gene that dilutes black pigment. It is an autosomal (not sex-linked) incompletely dominant gene. Incompletely dominant means that a bird with one copy versus two copies of the allele will display an intermediate result of the trait: blbl = off, Blbl = partially on, BlBl = completely on

For example, frizzle is another incompletely dominant gene. One copy curls the birds feathers noticeably, whereas two copies curls the feathers so much that they become brittle and break easily.

Back to blue--two copies of the not-blue allele, bl, and the black pigment is not diluted at all, at least not by the blue gene. One copy of the Bl allele and one of bl dilutes black pigment to a shade of bluish grey; two copies of Bl further dilutes the pigment to a lighter background shade with irregular, random splashes of darker pigment. A bird who is blbl is black--all black pigment in the bird is undiluted; a bird who is Blbl is blue, and one who is BlBl is splash.

For an analogy, if you were to take a pair of black pants and run them through the washer with a cupful of bleach, they would be lighter in shade when you finished the wash load. Okay, let's imaging that rather than putting them into the dryer you added more bleach to them, letting them sit wrinkled and soaking--essentially tie-dying them with bleach. The resulting pants would be lighter with irregular dark areas.


All birds have two copies of each gene (for this discussion we're ignoring the sex-linked genes, where this statement does not hold true for females).

When two birds breed and create a fertile egg, the egg receives one copy of each gene from each parent. If the parent is BlBl, he or she can only pass on that allele--all the offspring will receive Bl from the parent. The same thing holds true with a parent who is blbl. Carrying two copies of the same allele is called homozygous.

However, when a parent is Blbl, sometimes the parent will give Bl to offspring and sometimes bl. There is a 50% chance for each, which translates into about half the offspring receiving the Bl allele and the other half receiving the bl allele. When the two alleles carried are not the same, it is heterozygous.

At this point we can make a table to show the resulting percentages for the blue gene with the of pairing any two birds.

SplashXSplash
Bl Bl
Bl BlBl BlBl
Bl BlBl BlBl


BlackXBlack
bl bl
bl blbl blbl
bl blbl blbl

If parent A & parent B are both Bl, then all offspring will receive Bl from each parent, giving them the genotype of BlBl: splash. Likewise, if both parents are blbl, all offspring will be blbl: black.


SplashXBlack
bl bl
Bl Blbl Blbl
Bl Blbl Blbl

If parent A is BlBl and parent B is blbl, then all offspring will be Blbl, having receive Bl from parent A and bl from parent B. They will be blue.


SplashXBlue
Bl bl
Bl BlBl Blbl
Bl BlBl Blbl

If parent A is BlBl and parent B is Blbl, then they will always receive a copy of Bl from parent A. Half will receive a 2nd copy of Bl from parent B and the other half will receive bl from parent B. Half will be BlBl and half will be Blbl.


BlackXBlue
Bl bl
bl blBl blbl
bl blBl blbl

Essentially the same thing occurs if parent A is blbl and parent B is Blbl--it is just that instead of all receiving a copy of Bl from parent A, they receive bl. Half will be blbl & half will be blBl. Since the dominant gene is always listed first, Blbl.


BlueXBlue
Bl bl
Bl BlBl Blbl
bl Blbl blbl

When both parents are heterozygous, Blbl, it is slightly more complicated. Half will receive Bl from parent A, and half of those will also receive Bl from parent B, the other half of the one who received Bl from parent A will receive bl from parent B. Likewise, of the half who receive bl from parent A, half will receive Bl and the other half bl from parent B. Add those up and 50% will be homozygous--split equally between BlBl & blbl (25% each). The other half will be heterozygous.

 

[Sonoran Silkies]

Obviously the 'Blues' must carry more than the 'blue' color gene.

No, see my post above. Blue & splash both result from the blue gene. No additional genes are needed for these colours to express in a bird.​

 

[Sonoran Silkies]

You mean like a genetic calculator or something?

I think something more basic is needed first

THEN the calculator

 

[Smokin Silkies]

wow sonoran! That is alot of info! but this is what I am looking for. It is still very confusing but the more I read about it and learn, the easier it will be to understand. After reading this I do understand more, and I appreciate the help from everybody! I'm glad I don't plan on breeding anytime soon...lol. This will take me a long time to fully understand everything I need to know before breeding. Thanks all!

 

[Sonoran Silkies]

Partridge & grey are the same colour with one major genetic difference--the silver/gold gene. Greys are silver; partridges are gold.

Buff is a dilute version of red, however with red, black is allowed; it shouldn't be present in a buff bird.

White in silkies is recessive, so two whites paired together should only produce white. However, white acts as an OFF switch that prevents pigment from being placed in the plumage, essentially turning off the expression of colour and pattern genes that are also present in the bird. A bird who is genetically blue (or buff or partridge or grey or black or a mish-mash of the above) who also carries two copies of recessive white will be white, and there will be no indication of what other genes are actually present in the bird.

 

[Smokin Silkies]

So if that genetically blue, that carries 2 whites genes is white.....somewhere along the line, if kept mated to whites should stay white, or could it give off a blue color at any time?

 

[Smokin Silkies]

Oh wait, you said white is the recessive so that particular bird should 'not' show the blue gene ever....right?

 

[BoiseBubba]

Here,this may help, its a color calculator(spelling?)

http://www.breedbook.org/?action=geneticscalculator&tab=CHICKEN

 

[Sonoran Silkies]

Go play with the genetics calculator Henk has listed at the end.

Recessive white to recessive white should always result in a white bird. If paried with a non-white bird, however the offspring won't be white unless that bird also carries a copy of recessive white. But lets assume that several generations have gone past from that genetically blue bird--the genes of each parent have been meshed together in each generation, so that what was pure and simple is almost certainly not any longer.

 

[Smokin Silkies]

Thank You so much! You have been a wonderful help!!!