Enzyme polymorphism in feral, outbred and inbred rats (Rattus norvegicus)

Abstract

Polymorphism at 25 loci coding for liver enzymes was studied in two feral, three outbred and three inbred rat strains by starch gel electrophoresis. No variation was found at 14 loci, and a low degree of polymorphism was detected at three. Eight loci were polymorphic in more than one population. The average degree of heterozygosity per locus per individual feral rat was 007. The degrees of heterozygosity observed in the outbred and inbred strains were lower, from 0006 to 0012. Contrary to expectation, the inbred strains were neither monomorphic nor appreciably less heterozygous than the outbred ones. The heterozygosity of the inbred strains was primarily due to two polymorphic loci, G-3-pdh and -Gpdh. The reason for this polymorphism is probably the superior homeostasis of the heterozygotes.