The V-J-intergenic region of the human kappa locus

The 23-kb region between the V kappa and J kappa gene clusters was investigated in some detail. The region was found to be free of V kappa genes or V kappa gene-like structures, confirming the previous supposition that the V kappa gene B3 is the J kappa proximal V kappa gene. The B3-J kappa distance of 23 kb was found to be the same in the DNAs of several individuals. A HindIII restriction fragment length polymorphism was detected within this region. A sequence of 533 bp located approximately in the middle of the region has a highly homologous counterpart (called homox) on another chromosome. The two sequences are 96% identical. Possible mechanisms for the generation of such a duplicate are discussed.