Abstract
A new variant of kidney esterase in the DK/Nac rat strain is reported. The new esterase was tentatively named ES-4C determined by a third allele of the Es-4 locus of Linkage Group V (LGV). Strain distribution was surveyed using 17 inbred strains, but no strain except for the DK/Nac strain possessed the ES-4C type. Although we surveyed outbred stocks (Jcl:Wistar and Jcl:SD) we could not find rats carrying the ES-4C type. Genetic analysis of the ES-4C type was carried out using mating experiments between DK/Nac and BUF/Nac (ES-4B). The results indicated that the new variant was controlled by the Es-4 locus and it was named the Es-4 C allele.