DOMINANT SPOTTING IN A NATURAL-POPULATION OF THE VOLE

Dominant spotting was discovered in a natural population of the montane vole, Microtus montanus, in Grand Teton National Park, Wyoming. Extensive laboratory breeding tests established that this is probably a mutation at the W locus, and is homologous with dominant spotting in Mus and in Microtus arvcilis. The heterozygotes are white-spotted agouti individuals. Most of the homozygous dominant white individuals die in utero or shortly after birth. Survivors are black-eyed whites. They remain smaller than their agouti or spotted littermates throughout their entire life, are invariably sterile, and are probably anemic. This is the first report of dominant spotting in the montane vole, Microtus montanus. It is also the first report of a naturally occurring coat-color mutation from the population of Microtus montanus in Grand Teton National Park. © 1979 American genetic association.