Genetic polymorphism at the kappa chain locus in mice: comparisons of restriction enzyme hybridization fragments of variable and constant region genes.

Variable (V kappa) and constant (C kappa) region genes of the mouse kappa light chain have been compared in inbred strains and in geographically isolated or genetically separated populations of mice by Southern blot analysis of endonuclease-restricted germline DNA. In most cases, the C kappa gene is found on a single restriction fragment while the V kappa genes of the V kappa 19 and V kappa 21 groups are each found on several (6-18) fragments. The restriction fragment (RF) patterns of V kappa 19 and V kappa 21 groups are both polymorphic when compared among inbred mouse strains. Southern blot patterns of V kappa 21 and V kappa 19 of inbred strains are also found among some geographically isolated populations of mice, suggesting that inbred strains acquired kappa loci from different subspecies. Some populations of geographical isolates show V kappa 21, V kappa 19, and C kappa contexts similar to inbred mice while more distantly related species within the genus Mus and laboratory rats show no apparent similarity in context to inbred strains. Variable region genes determining the RF patterns of V kappa 19 and V kappa 21 appear to be linked to each other and to the C kappa and Lyt-3 loci.