Albinism and its inheritance in populations of the montane vole.

Albinism was observed in natural populations of the montane vole, Microtus montanus nanus, in Grand Teton National Park, Wyoming. Two individuals, apparently littermates, were captured in a high density population in 1976, and a third was taken at the same site from a high density population one year later. Laboratory breeding tests established that albinism in this species is inherited as an autosomal homozygous recessive. Territorial polygyny and the occurrence of extended maternal families at high densities may result in significant amounts of inbreeding as evidenced by presumably maladaptive homozygous recessive pelage variants such as albino.