Mice heterozygous for the varitint-waddler spontaneous mutation (Mcoln3Va) are deaf and show circling behavior, head-tossing, and hyperactivity. Heterozygotes circle somewhat less than some of the other circling mutants. Their coats are variegated with patches of normal-colored, diluted, and white fur. Homozygotes show more intense behavioral abnormalities than heterozygotes, and their coats are white, except for small patches of unaltered color near the ears and base of the tail. The pathological changes in heterozygotes include degeneration of the organ of Corti, stria vascularis, spiral ganglion, saccular macula, cristae ampullares, and vestibular ganglion. In homozygotes the degenerative changes are more severe and also include the utricular macula. Viability of heterozygotes is nearly normal, but fertility is reduced. Mortality is very high in homozygotes, and very few of the survivors are fertile. Compound heterozygotes for the two alleles (Mcoln3Va-J/Mcoln3Va) are similar to Mcoln3Va-J/Mcoln3Va-J mice but are smaller with more white spotting and abnormal behavior. They are deaf and circle vigorously. Viability and fertility of Mcoln3Va-J/Mcoln3Va mice are considerably reduced. This strain is also homozygous for the rex spontaneous mutation (Re) and segregating for Danforth's short tail (Sd).
