Multiple sequences related to a constant-region kappa light chain gene in the rabbit genome

Four allelic genes control kappa light chain allotypes in the rabbit. Amino acid sequence studies have revealed an extensive divergence (22%-33%) in the alternative forms of the kappa constant region (b4, b5, b6 and bg). Furthermore, independent studies have shown that a rabbit could express a wrong allotype. To assess the hypothesis that b allotypes are encoded by duplicated genes with a polymorphic control mechanism, we have analyzed the DNAs of four different homozygous rabbits using the Southern blot hybridization technique, with a cloned b4 C_κ probe. DNAs of individual b4, b5, b6 and b9 rabbits were cleaved with Eco RI, Kpn I and Pst I restriction endonucleases. Comparative analysis of restriction patterns shows that all four rabbit DNAs contain multiple DNA fragments hybridizing with the probe under low- and high-stringency washing conditions. In addition, each restriction pattern is distinct, suggesting that the C_κ genes are organized differently in animals expressing different allotypes.