What Causes the Splash coloring?

[beakkeeper]

OK, folks, highschool genetics is all I got, so simple terms would be nice!

lol. I know that if you breed blue to blue, you will get splash, black, and some blue. This would lead me to believe that the allele for blue is codominant with the one for black. So a splash would have B (black) and B1 (blue) alleles, black would have BB, and blue would have B1B1. Once again, a little rusty on the genetics... but I am really curious!

Thanks in advance!

 

[Blisschick]

Just for clarity, you are asking about the Andulasian blue gene. There is also a self-blue gene, but it doesn't work the same way. Some people get confused by that.

Any time you have one blue gene paired with at least one black gene, you will get a blue colored chicken. If you have a blue gene paired with both black genes, you will get splash. Blue also has a dosage effect that's not quite understood, so if a blue and a splash, or even two splashes were to breed, the resulting offspring will be even lighter than the parents, to the point the blue can appear white.

This is how it would look (this is very simplified):

E = extended black
Bl = blue

BlE/E = blue
BlE/BlE = splash

 

[tadkerson]

I just want to clarify some information. I agree with Stacey; who's explanation was on the mark.

Alleles are found at the same locus (position) on a chromosome. So the blue gene and the extended black gene are not alleles. The blue gene and the extended black gene are found at different loci.


The blue gene is a diluter of black pigment. The allele to the blue gene Bl is the non diluting gene bl+. The extended black gene (E) is an allele to other genes like wheaten (e^Wh) and wild type e^+.

To make sure a bird is completely black, black birds also have the melanotic gene (Ml/Ml) and other genes that extend black.

I believe (my own ideas based upon my work with blue) that that light colored ( blue or splash) birds have different black extenders than dark birds and the lighter birds are most likely birchen at the E locus. I need to do more work with the blue and gather data to statistically support my ideas.

A blue bird is Bl/bl+, E/E, Ml/Ml

a black bird is bl+/bl+, E/E, Ml/Ml

splash is Bl/Bl, E/E, Ml/Ml

There is some linkage involved with the blue and melanotic genes but they are far enough apart that the linkage is not a problem.


Tim