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Introduction

All the human immunoglobulin (IG) and T cell receptor (TR) genes were identified and sequenced by the end of 1998.
In 1999, IMGT gene names and IMGT gene definitions for all the human IG and TR genes were approved by the HUman Genome Organization (HUGO) Nomenclature committee [1,2] and reciprocal links made between IMGT, Entrez Gene (NCBI) and NCBI genome.

In Febrary 2001, two versions of the human genome sequence were published in Nature [3] and Science [4], respectively:

In the Nature and Science papers [3,4], there is no new or detailed information concerning the IG and TR genes which are mentioned only occasionally. However a careful analysis of the maps published in these papers allows to confirm the chromosomal localizations of the seven main loci: IGH, IGK and IGH for the immunoglobulins, TRA, TRB, TRG and TRD for the T cell receptors, which were previously determined by the analysis of translocations involving these loci in leukemia and lymphoma.

Positions of the IG and TR loci on chromosomes (2001)

Positions of the human IG and TR loci on chromosome were estimated from the maps published in [3] and [4] (M.-P. Lefranc, 20/02/2001).
Positions are described from the telomeric end of the chromosome short arm (p) to the telomeric end of the long arm (q).

Size of the human haploïde genome : 3 Gb (3 billion bases, 3.109 bases).

Chromosomes Reference Chromosome length in Mb (1) Centromere position (3) IG and TR loci
Locus Position in Mb (4) Locus orientation (5) Chromosomal localization (5)
2 [3] 256 96-99a
(p11.1-q11.1)		 IGK 94 IGK REV 2p11.2
[4] 251 94.9c IGK 93.5
7 [3] 173 60.5-63.5a
(p11.1-q11.1)		 TRG
TRB		 40.5
154		 TRG
TRB		 REV
FWD		 7p14
7q34
[4] 150 54.7c TRG
TRB		 37
131.7
14 [3] 113 16b
(pter-q11.1)		 TRA/TRD
IGH		 17.5
111.5		 TRA/TRD
IGH		 FWD
REV		 14q11.2
14q32.33
[4] 91 (2) 0.2d TRA/TRD
IGH		 2.5d
89d
22 [3] 48 13b
(pter-q11.1)		 IGL 19 IGL FWD 22q11.2
[4] 38 (2) 0.2d IGL 7d

Mb: megabase (106 bases)

Overview per locus

Positions are described from the telomeric end of the chromosome short arm (p) to the telomeric end of the long arm (q).

Locus
[5,6]		 Chromosomal localization Locus position in Mb [5] Distance from
centromere in Mb [6]
[3] [4]
IGH 14q32.33 111.5 ~105 104.6-105.6 (6) 95.5 (8)
IGK 2p11.2 94 93.5 88.5 2
IGL 22q11.2 19 ~20 19-20 6
TRA 14q11.2 17.5 ~18.5 17.8-18.8 1.5
TRB 7q34 154 131.7 147.7-148.4 90.5 (9)
TRG 7p14 40.5 37 38.6-39.8 (7) 20
TRD 14q11.2 17.5 ~18.5 18-18.5 1.5

Update (August 2003)

Positions are described from the telomeric end of the chromosome short arm (p) to the telomeric end of the long arm (q).

Locus Chromosomal localization Locus position in Mb
Update 2003 [7]
IGH 14q32.33 104.2-105.4
IGK 2p11.2 89.04-90
IGL 22q11.2 20.710-21.602
TRA 14q11.2 (10)
TRB 7q34 141.2-142
TRG 7p14 37.90-38.12
TRD 14q11.2 (10)

IMGT Genes on the Ensembl Genome Browser (November 2005) (IMGT index)

IG and TR locus delimitations in GRCh38.p13

Positions are described from the telomeric end of the chromosome short arm (p) to the telomeric end of the long arm (q).

Locus Chromosomal localization Locus position in bp
in GRCh38.p13 [8]		 Locus orientation Most external genes in the locus (11)
IGH 14q32.33 105,586,937-106,879,844 REV IGHA2 (3', cen) - IGHV(III)-82 (5', tel)
IGK 2p11.2 88,857,361-90,235,368 REV IGKC (3', tel) - IGKV3D-7 (5', cen)
IGL 22q11.2 22,026,076-22,922,913 FWD IGLV(I)-70 (5', cen) - IGLC7 (3', tel)
TRA 14q11.2 21,621,904-22,552,132 FWD TRAV1-1 (5', cen) - TRAC (3', tel)
TRB 7q34 142,299,011-142,813,287 FWD TRBV1 (5', cen) - TRBV30 (3', tel)
TRG 7p14 38,240,024-38,368,055 REV TRGC2 (3', tel) - TRGV1 (5', cen)
TRD 14q11.2 21,924,138-22,469,614 FWD TRAV14/DV4 (5', cen) - TRDV3 (3', tel)
IMGT notes:
(1) Length in megabases (Mb) from pter to qter, except if indicated (see note 2). The lengths were estimated from the maps published in [3] and [4].
(2) Length in megabases (Mb) from the centromere to qter for the acrocentric chromosomes 14 and 22.
(3) Centromere positions in megabases (Mb) from pter. In reference [3], the centromere is depicted as encompassing the p11.1 and q11.1 bands(a), except for the acrocentric chromosomes 14 and 22, for which the length in megabases which is provided is that from pter to cen included (pter-q11.1)(b).
In reference [4], the centromere is depicted as a line at a position approximated by the transition from p to q arms along the genome sequence(c), except for the acrocentric chromosomes 14 and 22 for which the centromere is placed at the beginning of the sequence analysis(d).
(4) Reference [3]: positions in megabases are directly from the map. (d) indicates positions from the centromere.
Reference [4]: IG and TR positions (not indicated on the map in reference [4] were estimated by comparing positions of other genes identified in their neighbourhood, on both [3] and [4] maps. A purple rectangle, indicating a "immune response gene" was found on the expected strand (orientation) and at the expected position, except for the IGH locus.
(5) Locus orientation and cytogenetic chromosomal localizations are from IMGT Repertoire.
REV = reverse, FWD = forward, compared to the direction from the short arm telomere to the long arm telomere.
In reference [3], the TRG and TRB loci are localized on the map at 7p14.1 and 7q34.1, respectively. However translocation data in the literature do not reach that degree of resolution: translocations breakpoints involving the TRG locus has been described at 7p15-p14, 7p15 or 7p14 and translocations breakpoints involving the TRB locus at 7q34-q35, 7q34 or 7q35. IMGT chromosomal localizations of the TRG (7p14) and TRB (7q34) loci will be described more precisely when the correspondence between the cytogenetic location and the physical map and sequence is confirmed and/or needed.
(6)IGHM is at 105.6 Mb from pter.
(7)TRGV9 is at 38.6 Mb from pter.
(8)The IGH locus is at 1.5 Mb from the 14qter telomer (1.5 Mb [3], 2 Mb [4]).
(9)The TRB locus is at about 20 Mbp from the 7qter telomer (19 Mb [3], 21.7 Mb [4]).
(10) Although the human TRA and TRD genes are entered in the genome view, the detailed map of these loci is not yet available.
(11)3'= locus 3' end; 5'= locus 5' end; cen= centromeric; tel= telomeric.
References:
[1] Lefranc, M.-P. and Lefranc, G. The Immunoglobulin FactsBook, Academic Press, London, 458 pages (2001) ISBN: 012441351X
[2] Lefranc, M.-P. and Lefranc, G. The T cell receptor FactsBook, Academic Press, London, 398 pages (2001) ISBN: 0124413528
[3] Lander, E. S. et al. Initial sequencing and analysis of the human genome. Nature, 409, 860-921 (2001) PMID: 11237011
[4] Venter, J. C. et al. The sequence of the human genome. Science, 291, 1304-1351 (2001) PMID: 11181995
[5] Ensembl (search by M.-P. Lefranc, 07/06/2001). The numbers are not meant to give limits of the loci, but to indicate positions at which IG or TR genes were identified in Ensembl.
[6] Data deduced from ref. [2] (M.-P. Lefranc, 20/06/2001).
[7] Homo sapiens genome view build 33 (NCBI) (search by M.-P. Lefranc, 25/08/03)
[8] Homo sapiens genome view build 106 GRCh38 Primary Assembly (NCBI) (19/11/2014)
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