Pondering Sprigs... Pictures please!

Doesn't Asmundson's study show that sprigs are polygenic and dominant? From what I have read it sure seems to act that way. A dominant trait is going to eventually increase within a given population, but if it only expresses in the presence of another gene, it will lie latent until that other gene is introduced.

I think this is why folks with a closed flock often don't find carnation combs or sprigs until they bring in outside blood that possesses the other "half" of the carnation comb A+B combination.

If it were simple autosomal recessive, it seems the carnation comb and sprigs would not persist in so many knowledgeable breeders' lines.

If it is indeed polygenic and requires two dominant genes to express a sprig or carnation comb, it could act as a single autosomal recessive.

Aabb x aaBb Two clean combed carriers

AabB - sprig
Aabb - clean comb carries one half of sprig combo
aabB - clean comb carries other half of sprig combo
aabb - clean comb, non-carrier (the holy grail!)

This gives you the same 75/25 ratio as two heterozygous autosomal recessives. It's just trickier to test breed and eliminate.

coopslave wrote:Sprigs are usually easy to see on a male, single comb. Tougher on females, but if you look close you can usually see them. I have not thought of them on a pea comb, does that happen?
I am not sure if I have any photos of them or not, will have to go through the archives.