IMGT/GENE-DB: genomic reference sequences for human and mouse IG and TR genes and alleles

Abstract

The immunoglobulin (IG) and T cell receptor (TR) major loci span about 6 Megabases (Mb) of the human genome on chromosomes 2, 7, 14 and 22, and 9 Mb in mouse on chromosomes 6, 12, 13, 14 and 16. There are seven major loci: three IG loci (IGH, IGK, IGL) and four TR loci (TRA, TRB, TRG, TRD), with a distinct repartition of the variable (V), diversity (D), joining (J) and constant (C) genes. The human genome comprises a total number of , depending on the haplotypes, per haploid genome [1, 2] of which 531-588 genes are located in the major loci (distributed in 369-418 V, 32 D, 105-109 J and 25-29 C genes). There are also 77 orphons (68 IG and 9 TR) including two processed IG genes, outside the major loci. The number of functional IG and TR genes is 5-4 6-6 7-5 5-5 6-7 7-6 5-6 6-8 7-7 5-7 6-9 7-8 5-8 7-9 13 10-3 IMGT/GENE-DB entry for Mus musculus IGHV1-58Genomic The human genome comprises 371-422 IG genes (303-354 genes located in the 3 major IG loci and 68 orphons), per haploid genome.The functional IG genes (136-171 depending on the haplotypes) are located in the 3 major IG loci. Different molecular mechanisms (V-J and V-D-J rearrangements, N-diversity, and for IG, somatic hypermutations), unique to vertebrates, allow to create a huge repertoire of 2x10 12 IG (or antibodies) per individual.The human genome comprises 237-243 TR genes (228-234 genes located in the 4 major TR loci and 9 orphons), per haploid genome.The functional TR genes (172-185 depending on the haplotypes) are located in the 4 major TR loci. Different molecular mechanisms (V-J and V-D-J rearrangements, N-diversity), unique to vertebrates, allow to create a huge repertoire of 2x10 12 TR per individual.