Mice homozygous for the quivering 3 Jackson spontaneous mutation (Sptbnqv-3J) are very similar to mice homozygous for the quivering-Jackson mutation (Sptbnqv-J). Homozygous quivering mutant mice are characterized by locomotor instability, pronounced quivering, deafness, varying degrees of paralysis of the hindlegs, clasping of the hindlegs when held up by the tail, and priapism in most males. Serial sections of the brain, cord, and nerve roots reveal no abnormalities, and urinary amino acids are normal. The inner ear is histologically normal and has normal thresholds for compound action potentials at the round window. However, the thresholds for potentials in the inferior colliculus are twice as high as normal, showing that the deafness, unlike that of any other deaf mutants in the mouse, is of central origin. Viability of homozygous mutant mice at weaning is normal, but the life span is short, the majority dying before 5 months of age. Males are sterile, but have been used successfully for in vitro fertilization. Females may be fertile and nurse their young.
