Abstract
The rolling gene, rol, causing abnormal locomotor activity was an allele of the tottering, tg, locus; this locus was closely linked to the non-specific esterase-1 locus on chromosome no. 8. The tg locus has 3 mutant alleles: tottering, tg; leaner, la; and rolling, rol. The mice with genotype rol/tg show clinical symptoms similar to rol/rol rather than to tg/tg. The symptom of ataxia occurs at about 2 wk of age in this mutant, which survives to adult age.