Assignment of tremulous body mutant gene zitter (zi) to linkage group IV of the rat (Rattus norvegicus).

Zitter rats are mutants from a Sprague-Dawley rat colony. They exhibit whole body tremors, defective overhairs, bent whiskers, and spongiform encephalopathy of the central nervous system. The anomalies are caused by an autosomal recessive gene, zitter (zi). We examined the linkage relationships between zi and 14 polymorphic loci in two backcross series, (zitter x TM)F1 x zitter and (zitter x BN)F1 x zitter. Linkage of the zi locus to Hao-1 and Svp-1 indicated that the zi locus belongs to linkage group IV. The gene order was zi--(9.2% +/- 2.8%)--Hao-1--(27.7% +/- 6.5%)--Svp-1.