White skin: a Z-linked recessive mutation in the fowl

A 6-week-old pullet was noted with white shanks and beak from a strain of SC White Leghorns, pedigree-bred as a closed flock since 1948. Mating of the mutant to males with yellow skin produced only yellow skinned progeny. The F2 progeny consisted of equal numbers of yellow or white shanked pullets and yellow shanked sons. This distribution indicates that the new trait is due to a mutation on the Z chromosome. The symbol y is suggested for the new allele. Tests for linkage with late feathering K and with id revealed that the new locus is not closely linked with either. The white shank color trait is quite accurately identified in the newly hatched chick.