Dominant White

Dominant white is one of the earliest and best studied chicken mutations. Allele symbol I.

Etymology and Discovery

The symbol I stands for the inhibiting effect on pigmentation.

Degree of dominance

Most dominant of the PMel17 mutations, but still mostly incomplete dominant; see also Heterozygosity.

Phenotypic effect

Black feather areas are replaced by white.

chick down

Dominant white is expressed in the chick down and does not help identifying the other mutations.

Heterozygosity

Heterozygous dominant white is somewhat leaky. Black flecks are possible, and the general tint of the white areas can be grayish.

• Heterozygous with smoky I^s. The white areas are partially reverted to a darker gray color, resembling Andalusian blue.
• With dun I^d, the dark flecks, if any are present, would be dun/chocolate colored.

Epistatics

Covers all other black diluters. When in one dose the (black) flecks can shown the degree of dilution by the other black diluter genes.

Role in certain complex phenotypes

May be present in the buff color of some chicken breeds and adds a special quality to it. Buff is also used for other colorations that are dominant white patterned, because the tint of the pheomelanin is often more diluted.