| Introduction |
- IMGT/GeneFrequency is part of IMGT, the international ImMunoGeneTics information system®,
http://www.imgt.org [1].
IMGT/GeneFrequency, created by LIGM (Université Montpellier II, CNRS), on the Web since August 2003, is a tool which provides a graphical representation of the numbers of cDNA and genomic IMGT/LIGMDB sequences containing rearranged immunoglobulin (IG) and T cell receptor (TR) genes.
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Gene frequency is calculated for fully annotated IG and TR rearranged sequences (cDNA and genomic DNA)
extracted from IMGT/LIGM-DB, according to the user query.
IMGT/GeneFrequency results are shown as graphical representations which comprise histograms localized at the V, D and J gene positions
along the locus and proportional to the number of IMGT/LIGM-DB cDNA and genomic sequences containing that gene and answering the user selection (IMGT Repertoire>Locus representations).
Clicking on the bars of the histogram gives access to IMGT/GENE-DB and IMGT/LIGM-DB entries answering the user selection.
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Sequences extracted by IMGT/GeneFrequency from IMGT/LIGM-DB are necessarily fully annotated, either manually
(indicated by "annotators" in the ID line of the flat files, example: AF306358) or
by the IMGT/Automat tool [2] ("automatic" in the ID line, example: AF306350).
These flat files contain the IMGT gene names [3,4] which are required for the search by the IMGT/GeneFrequency tool.
Note that genomic DNA sequences which contain more than one V gene
[for instance, one rearranged V-D-J gene and one (or several) germline gene(s)]
are not available to the query.
| IMGT/GeneFrequency Search page |
In the IMGT/GeneFrequency Search page, the selection takes place in three stages:
- Select a Species:
- At present only Homo sapiens and Mus musculus sequences are available.
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- Histogram for:
- All IMGT/LIGM-DB rearranged sequences
- or Specificity (choice in a multiple list, for example "anti-thyroid peroxidase (TPO)")
Following the specificity choice, only the loci that contain genes which answer the selected specificity will be offered for selection in the "Individual locus" box.
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- Select Loci:
Two different scales (200 kb per line or 400 kb per line) are available, select a scale to visualize the locus.
- IG or TR loci:
- IGH, IGK, IGL, for immunoglobulin
- TRA/TRD, TRB, TRG, for T cell receptor
The scale depends on the locus length.
- Individual locus:
- IGH
- IGK
- IGL
- TRA/TRD
- TRB
- TRG
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- Click on the "Search" button to valid your search.
| IMGT/GeneFrequency results |
Results for All IMGT/LIGM-DB rearranged sequences (IG or TR loci)
The IMGT/GeneFrequency results for all IMGT/LIGM-DB rearranged sequences (IG or TR loci) query comprise:
- Title
The title indicates the species, the IG loci (IGH, IGK, IGL) or the TR loci (TRA/TRD, TRB, TRG)
- Graphical representation
- The three IG loci (IGH, IGK and IGL) or the four TR loci (TRA/TRD, TRB and TRG) are displayed, depending on the selection.
The scale depends on the locus length.
- The graphical representation comprises histograms localized at the V-GENE, D-GENE and J-GENE positions in the locus.
- Gene positions are from IMGT/LocusView. Only genes that have rearranged sequences answering the query (species, specificity, loci) are displayed.
- The height of the vertical bar is proportional to the number of IMGT/LIGM-DB cDNA and genomic sequences containing a given gene and answering the user selection. The color of the vertical bar indicates the gene type, according to IMGTScientific Chart>Color Menu.
- The C genes are shown by squares.
- Zoom
A zoom is available for D-GENEs and J-GENEs by clicking on the corresponding areas.
- Results summary (Number of sequences per locus and per gene)
A summary table gives access to the number of IMGT/LIGM-DB sequences with rearranged gene foreach locus, Group and Gene. Clicking on numbers gives access to the detailled list of IMGT/LIGM-DB sequences (accession number and description).
Clicking on loci or groups gives access to the corresponding section in the table.
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Results for All IMGT/LIGM-DB rearranged sequences (Individual locus)
The selected locus (IGH, IGK, IGL, TRA/TRD, TRB or TRG ) is displayed depending on the selection, and in the chosen scale (200 kb or 400 kb).
The IMGT/GeneFrequency results for "Individual locus" query comprise:
- Title
The title indicates the species and the locus with its chromosomal localization IMGTRepertoire>Chromosomal localizations.
- Graphical representation
- The graphical representation comprises histograms localized at the V-GENE, D-GENE and J-GENE positions in the locus.
- Gene positions are from IMGT/LocusView. Only genes that have rearranged sequences answering the query (species, specificity, locus) are displayed.
- The height of the vertical bar is proportional to the number of sequences answering the query in IMGT/LIGM-DB. The color of the vertical bar indicates the gene type, according to IMGTScientific Chart>Color Menu.
- The C genes are shown by squares.
- Zoom
A zoom is available for D-GENEs and J-GENEs by clicking on the corresponding areas.
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Results for Specificity (IG or TR loci)
The IMGT/GeneFrequency results for selected specificity (IG or TR loci) query comprise:
- Title
The title indicates the species, the IG loci (IGH, IGK, IGL) or the TR loci (TRA/TRD, TRB, TRG)
- Graphical representation
- The three IG loci (IGH, IGK and IGL) or the four TR loci (TRA/TRD, TRB and TRG) are displayed, depending on the selection.
The scale depends on the locus length.
- The graphical representation comprises histograms localized at the V-GENE, D-GENE and J-GENE positions in the locus.
- Gene positions are from IMGT/LocusView. Only genes that have rearranged sequences answering the query (species, specificity, loci) are displayed.
- The height of the vertical bar is proportional to the number of IMGT/LIGM-DB cDNA and genomic sequences containing a given gene and answering the user selection. The color of the vertical bar indicates the gene type, according to IMGTScientific Chart>Color Menu.
- The C genes are shown by squares.
- Zoom
- A zoom is available for D-GENEs and J-GENEs by clicking on the corresponding areas.
- Information for all genes
- For each locus and for each gene, the IMGT/LIGM-DB cDNA and genomic sequences with rearranged genes are indicated.
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Results for specificity (Individual locus)
The selected locus (IGH, IGK, IGL, TRA/TRD, TRB or TRG ) is displayed depending on the selection, the chosen specificity and in the chosen scale (200 kb or 400 kb).
The IMGT/GeneFrequency results for "Individual locus" query comprise:
- Title
The title indicates the species, the specificity (selected in the IMGT/GeneFrequency Search page), and the locus with its chromosomal localization
- Graphical representation
- The graphical representation comprises histograms localized at the V-GENE, D-GENE and J-GENE positions in the locus.
- Gene positions are from IMGT/LocusView. Only genes that have rearranged sequences answering the query (species, specificity, locus) are displayed.
- The height of the vertical bar is proportional to the number of sequences answering the query in IMGT/LIGM-DB. The color of the vertical bar indicates the gene type, according to IMGTScientific Chart>Color Menu.
- The C genes are shown by squares.
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- Zoom
- A zoom is available for D-GENEs and J-GENEs by clicking on the corresponding areas.
- Information for all genes
- For each locus and for each gene, the IMGT/LIGM-DB cDNA and genomic sequences with rearranged genes are indicated.
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Access to IMGT/LIGM-DB and IMGT/GENE-DB:
Clicking on the vertical bar of a gene gives access to a link to IMGT/GENE-DB entry for that gene an to a list of IMGT/LIGM-DB accession numbers answering to the user selection.
Each IMGT/LIGM-DB accession number has a link to the resulting page in IMGT/LIGM-DB and the IMGT/GENE-DB entry for the gene has a link to the resulting page in IMGT/GENE-DB.
Particularities of the IGK locus:
- Eight genes of the IGK distal cluster (IGKV1D-12, IGKV1D-13, IGKV1D-33, IGKV1D-37, IGKV1D-39, IGKV2D-28, IGKV2D-40 and IGKV6D-21) have a high similarity with the corresponding genes from the proximal cluster (IGKV1-12, IGKV1-13, IGKV1-33, IGKV1-37, IGKV1-39, IGKV2-28, IGKV2-40 and IGKV6-21, respectively). Expressed sequences cannot be therefore assigned to the proximal or distal gene. For these 8 gene pairs, in IMGT/GeneFrequency, the expressed sequences are assigned to the gene of the proximal cluster. Indeed, there is only a very low probability that expressed sequences are from genes of the distal cluster for the following reasons: distance from the J genes superior to 1300 kb, mechanism of inversion for the V-J rearrangements.
- For the other genes of the distal cluster, IMGT/GeneFrequency allows a normal histogram representation, if by any chance, expressed sequences are found.
See also:
References:
- Annotations
- Classification
- Gene
- Gene type
- IMGT Repertoire
- IMGT Scientific Chart
- Locus
- Molecule type
- Nomenclature
- Species
- Specificity
[1] Lefranc, M.-P., Nucleic Acids Res., 33, D593-D597 (2005), PMID:15608269, LIGM:291.
[2] Giudicelli V., Protat C., and Lefranc M.-P., The IMGT strategy for the automatic annotation of IG and TR cDNA sequences: IMGT/Automat, European Conference on Computational Biology ECCB 2003
[3] Lefranc, M.-P. and Lefranc, G., The Immunoglobulin FactsBook, Academic Press, 458 pages (2001) ISBN:012441351X
[4] Lefranc, M.-P. and Lefranc, G., The T cell receptor FactsBook, Academic Press, 398 pages (2001) ISBN:0124413528
| IMGT/GeneFrequency implementation and developments |
The IMGT/GeneFrequency tool was implemented using Perl (CGI, GD, SOAP, DBI, DBD) (DESS Bioinformatique, Université Montpellier II, France, stage at LIGM, Montpellier 14/04/03-31/08/03).
IMGT/GeneFrequency Documentation was written by Stéphanie Jeanjean, Elodie Boucomont (1ère année DUT Génie Biologique option Bioinformatique, IUT Clermont-Ferrand, antenne Aurillac, stage at LIGM, Montpellier 01/07/03-15/08/03) and François Ehrenmann Francois.Ehrenmann@igh.cnrs.fr.
The IMGT/GeneFrequency tool has been improved by François Ehrenmann and Marie-Paule Lefranc for an easier access on the web in July 2006.

In the IMGT/GeneFrequency Search page, the selection takes place in three stages:
Following the specificity choice, only the loci that contain genes which answer the selected specificity will be
offered for selection in the "Individual locus" box.









