title: Linkage of the four gamma subclass heavy chain genes.
abstract: The genes for the heavy-chain constant regions of the four gamma subclass immunoglobulins were identified in a set of overlapping mouse DNA fragments representing about 100 kilobase pairs (kb) of the mouse genome that was cloned from bacteriophage lambda libraries of BALB/c mouse embryo DNA. R-loop mapping studies show that the genes are located 5'-C gamma 3-34 kb-C gamma 1-21 kb-C gamma 2b-15 kb-C gamma 2a-3' and lie in the same transcriptional orientation. Two DNA segments, one of 19 kb and another of 15 kb, that surround the C gamma 2b and C gamma 2a genes, respectively, show considerable homology and implicate a tandem duplication mechanism in the evolution of this gene cluster.
mesh_terms: D000818:Animals; D010582:Bacteriophage lambda / Q000235:genetics; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004262:DNA Restriction Enzymes; D004622:Embryo, Mammalian; D004926:Escherichia coli / Q000235:genetics; D008040:Genetic Linkage; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007142:Immunoglobulin gamma-Chains / Q000235:genetics*; D051379:Mice / Q000235:genetics*; D008807:Mice, Inbred BALB C; D009693:Nucleic Acid Hybridization
chemical_list: D007143:Immunoglobulin Heavy Chains; D007142:Immunoglobulin gamma-Chains; D004247:DNA; D004262:DNA Restriction Enzymes