Genetics....

[paulh]

And "het BEL (grey head)" is another example of confusing phenotypes and genotypes. BEL (grey head) is the phenotype produced by a gene pair made up of two copies of a mutant gene named mojave. Mojave is the phenotype produced by a gene pair made up of a normal gene and a mojave mutant gene. I'd agree with het BEL (grey head) designation if the mutant gene was named BEL (grey head).

I think it is easier to parallel nomenclature between recessive, codominant, and dominant genes (as the pro geneticists do) than to make it up as we go along.

Two genes can make three gene pairs.

Albino is a mutant gene that is recessive to the corresponding normal gene.
Genotype = Two normal genes = homozygous normal. Phenotype (appearance) = normal.
Genotype = One normal gene and one albino gene = heterozygous albino. Phenotype (appearance) = normal.
Genotype = Two albino genes = homozygous albino. Phenotype (appearance) = albino.

Mojave is a mutant gene that is codominant to the corresponding normal gene.
Genotype = Two normal genes = homozygous normal. Phenotype (appearance) = normal.
Genotype = One normal gene and one mojave gene = heterozygous mojave. Phenotype (appearance) = mojave.
Genotype = Two mojave genes = homozygous mojave. Phenotype (appearance) = BEL (grey head).

Pinstripe is a mutant gene that is dominant to the corresponding normal gene.
Genotype = Two normal genes = homozygous normal. Phenotype (appearance) = normal.
Genotype = One normal gene and one pinstripe gene = heterozygous pinstripe. Phenotype (appearance) = pinstripe.
Genotype = Two albino genes = homozygous pinstripe. Phenotype (appearance) = pinstripe.

As it is now, just giving the phenotypes in a breeding problem requires translating them to genotypes before doing the problem. That can stop a newbie cold, even one who is familiar with the principles of genetics. Giving the genotypes allows anyone familiar with the principles of genetics to get the correct genotype answer to the problem even if that person is unfamiliar with the names to the corresponding phenotypes.