aviangenetics.com

What is complete autosomal dominant inheritance?

• In its simplest form, it involves 1 pair of genes with the wild type gene "p" being recessive to the mutant gene "P" in any combination. If the wild type/natural colour of a bird is purple and the mutant form is yellow, the following will be true:

pp = Purple Bird

Pp = Pink Bird

PP = Pink Bird

• In the following example,  one gene, we will call it "P", is responsible for colour. The "P" gene comes in 2 forms: "P" and "p". When the "P" gene is a capital "P", it is responsible for the pink colour and classified as dominant. When the "P" gene is a small "p", it is responsible for the regular/wild type pink colour and is classified as recessive. The are always 2 copies of the "P" gene in each individual. If an individual is pp, then it is purple/normal/wild type or is a homozygote (the pair of genes are the same) for the purple gene. Purple is the recessive form. If an individual is PP, then it is pink or in its dominant form. "PP" is a homozygote for the pink gene.  Most autosomal dominant mutations are incomplete, but some are complete (as this one is) meaning that the Split/heterzygote has the same phenotype (or appearance) as the homozygous dominant form (PP). The phenotype for a Pp individual is therefore pink like the PP individual . It is still a Split to purple, but it appears pink.

"P" = pink gene

"p" = purple gene

PP = pink individual

Pp = pink individual

pp = purple individual

(1) Pink (PP) X Pink (PP) = All Pink (PP)

(2) Purple (pp) X Purple (pp) = All Purple (pp)

(3) Pink (PP) X Purple (pp) = All Pink Split to Purple (Pp)

(4) Pink Split to Purple (Pp) X Pink Split to Purple (Pp) = 25% Pink (PP), 50% Pink Split to Purple (Pp), & 25% Purple (pp)

(5) Pink Split to Purple (Pp) X Pink (PP) = 50% Pink (PP) & 50% Pink Split to Purple (Pp)

(6) Pink Split to Purple (Pp) X Purple (pp) = 50% Pink Split to Purple (Pp) & 50% Purple (pp)