W D Dawson — Page 3 | PubMed Health

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Coat color genetics of Peromyscus: III. Golden-nugget--a recessive trait in the white-footed mouse, P. leucopus.

A novel pelage color variant appeared in a laboratory colony of white-footed mice (Peromyscus leucopus) from Massachusetts. The mature adult coat color of this variant exhibits a rich golden tan appearance on the dorsum with white underparts. The trait is inherited as an autosomal recessive. Phenotypic comparisons with other rodents suggest that the trait is attributable to an allele at the brown (b) locus. Under laboratory conditions homozygous or heterozygous golden-nugget Peromyscus do not differ significantly from the wild type in litter size, litter survival, nest defense, or body weight. The possibility that the allele confers some adaptive value in nature is considered. The trait is given the tentative designation bgn (golden-nugget).

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PubMedDate not supplied

Coat color genetics of Peromyscus: IV. Variable white, a new dominant mutation in the deer mouse.

The variable white mutation arose spontaneously in 1983 within a laboratory stock of wild-type deer mice (Peromyscus maniculatus). The original mutant animal was born to a wild-type pair that had previously produced several entirely wild-type litters. Other variable white animals were bred from the initial individual. Variable white deer mice exhibit extensive areas of white on the head, sides, and tail. Usually a portion of pigmented pelage occurs dorsally and on the shoulders, but the extent of white varies from nearly all white to patches of white on the muzzle, tip of tail, and sides. The pattern is irregular, but not entirely asymmetrical. Eyes are pigmented, but histologically reveal a decrease in thickness and pigmentation of the choroid layer. Many variable white animals do not respond to auditory stimuli, an effect that is particularly evident in animals in which the head is entirely white. Ataxic behavior is also prevalent. Pigment distribution, together with auditory and retinal deficiencies, suggests a neural crest cell migration defect. Breeding data are consistent with an autosomal semidominant, lethal mode of inheritance. The trait differs from two somewhat similar variants in Peromyscus: from dominant spot (S) in extent and pattern of pigmentation and from whiteside (ws), an autosomal recessive trait, in the mode of inheritance and viability. Evidence for possible homology with the Va (varitint-waddler) locus in house mouse (Mus) is presented. The symbol Vw is tentatively assigned for the variable white locus in Peromyscus.

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