THE IMMUNOGLOBULIN-KAPPA LOCUS OF PRIMATES

The immunoglobulin kappa genes of nonhuman primates were studied by us ing sequence information and hybridization probes derived from the hum an kappa gene regions. The following results were obtained: (1) V-kapp a gene probes of the three major human kappa subgroups hybridized to r estriction nuclease digests of DNA from the chimpanzees Pan troglodyte s (PTR) and Pan paniscus (PPA), the gorilla Gorilla gorilla (GGO), the orangutan Pongo pygmaeus (PPY), the macaque Macaca mulatta (MMU), the marmoset Callithrix geoffrei (CGE), and the bushbaby Galago demidovii (GDE), yielding patterns of decreasing similarity to the patterns of the human V-kappa multigene family. (2) The C-kappa gene segments of P TR, GGO, and PPY were 99.6, 97, and 93%, respectively, identical in se quence to the human C-kappa gene. A V-kappa gene in PTR, GGO, PPY, and MMU was 98, 96, 96, and 95%, respectively, identical to the most C-ka ppa proximal V-kappa gene, called B3. The other two J(kappa)-C-kappa p roximal V-kappa genes in human, B1 and B2, hybridize to restriction fr agments of sizes identical to that of DNA from humans and great apes. (3) The long range restriction maps of the human (HSA), PTR, and GQO k appa loci as established by pulsed field gel electrophoresis (PFGE) ar e quite homologous. According to the maps, however, and to hybridizati on studies with 11 duplication differentiating probes, there is only o ne copy of the locus in PTR and GGO. This means that the duplication o f large parts of the kappa locus as found in humans occurred after the branchpoint of human and great ape evolution. Despite the high simila rity in structural details, the kappa locus of the chimpanzee probably comprises only about half as many V-kappa genes as the human kappa lo cus. (4) Comparative PFGE experiments indicate that a V-kappa-orphon r egion on the long arm of chromosome 2 (cos108) was translocated by a p ericentric inversion that occurred after the separation of the GGO and PPY from the HSA and PTR clades. (C) 1995 Academic Press, Inc.