Variation in V lambda genes in the genus Mus.
The complement of Ig V lambda genes in nine species of feral mice representing the four extant subgenera of the genus Mus was examined and compared with that of BALB/c inbred mice. Although all inbred strains examined have two V lambda genes, there is variation in the number of copies of V lambda genes in the wild mice. All feral representatives of M. musculus domesticus, from which inbred strains are derived, have at least three V lambda genes, indicating that a V lambda gene may have been lost during the inbreeding process. At least three V lambda genes are also found in representatives of three other M. musculus subspecies, including the stock of M. musculus musculus "Czech II" shown to have at least 12 C lambda genes. In comparing the complement of V lambda and C lambda genes in these animals, evidence is found that supports a mechanism of lambda gene reiteration involving duplication of a unit containing a V lambda and two C lambda genes. However, the possibility that C lambda gene amplification occurred independent of V lambda gene evolution cannot be ruled out. M. spicelegus and M. spretus, species that are semifertile with M. musculus, have one to three V lambda genes. Species more distantly related to M. musculus, such as M. cookii and M. platythrix, appear to have more (four to six) V lambda genes. Greater V lambda gene heterogeneity is also found in these animals. We propose that the ancestors of the subgenus Mus had more V lambda genes than are seen in modern species and that the paucity of V lambda genes in M. musculus, M. spicelegus, and M. spretus may be the result of V lambda gene deletion events that occurred since the divergence of the ancestor of these three species and those of the distantly related species.
D000818:Animals; D000835:Animals, Wild; D002874:Chromosome Mapping; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004274:DNA, Recombinant / Q000378:metabolism; D005784:Gene Amplification; D014644:Genetic Variation; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D007146:Immunoglobulin lambda-Chains / Q000235:genetics*; D051379:Mice; D008806:Mice, Inbred AKR; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008811:Mice, Inbred DBA; D009115:Muridae / Q000235:genetics*
D004274:DNA, Recombinant; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region; D007146:Immunoglobulin lambda-Chains; D004262:DNA Restriction Enzymes