ALLELES: bln+ (wild-type), bln (mutant). Formerly, bl.
PHENOTYPE: Blonde affects the normal agouti-hair pigmentation in that the proximal regions of the hairs contain less pigmentation and the tips of the agouti hairs in the dorsal and lateral pelage do not possess black pigment. These effects combine to give the mutant animal a noticeably paler coloration than in the wild-type. The color dilution has a tan cast, in contrast to the grayer cast of the silver and platinum traits. Microscopically, the hairs contain somewhat fewer eumelanosomes than normal, and phaeomelanosomes are significantly reduced in the subterminal band.
Skin and eye pigment are also affected. The skin surrounding the eye is unpigmented; the dorsal tail stripe is diluted to pale gray; and the ears have no obvious coloration. Choroidal pigment in the eye is reduced in the blonde deer mouse.
INTERACTION: Blonde interacts with platinum to produce a "pseudoalbino" phenotype with markedly reduced pigmentation of pelage and eyes. Animals appear very pale gray with reddish eyes.
SOURCE: In 1976 two mutant deer mice were discovered in a full-sib mating between two wild-type progeny from unrelated wild-captured P.m. bairdii collected near Lansing MI.
REFERENCE: Pratt and Robbins (1982).