# Tandemly arrayed genes > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Tandemly_arrayed_genes > Markdown URL: https://mediated.wiki/source/Tandemly_arrayed_genes.md > Source: https://en.wikipedia.org/wiki/Tandemly_arrayed_genes > Source revision: 1314884576 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) Gene cluster created by tandem duplications **Tandemly arrayed genes** (**TAGs**) are a [gene cluster](/source/Gene_cluster) created by [tandem duplications](/source/Tandem_duplication),[1] a process in which one gene is duplicated and the copy is found adjacent to the original.[2] They serve to encode large numbers of [genes](/source/Gene) at a time. TAGs represent a large proportion of genes in a genome, including between 14% and 17% of the human, mouse, and rat genomes.[2] TAG clusters may have as few as two genes, with small clusters predominating, but may consist of hundreds of genes.[2] An example are tandem clusters of [rRNA](/source/Ribosomal_RNA) encoding genes. These genes are transcribed faster than they would be if only a single copy of the gene was available. Additionally, a single RNA gene may not be able to provide enough RNA, but tandem repeats of the gene allow sufficient RNA to be produced. For example, cells in a [human embryo](/source/Human_embryo) contain between five and ten million [ribosomes](/source/Ribosomes), and cell number doubles within 24 hours. In order to provide the necessary ribosomes, multiple [RNA polymerases](/source/RNA_polymerase) must consecutively transcribe multiple rRNA genes.[3] In some species, such as *[Arabidopsis thaliana](/source/Arabidopsis_thaliana)* and *[Oryza sativa](/source/Oryza_sativa)*, most TAGs are the result of unequal [chromosomal crossover](/source/Chromosomal_crossover) during [genetic recombination](/source/Genetic_recombination).[4] ## See also - [Satellite DNA](/source/Satellite_DNA) - [Tandem repeats](/source/Tandem_repeats) ## Notes 1. **[^](#cite_ref-FOOTNOTEPanZhang2008_1-0)** [Pan & Zhang 2008](#CITEREFPanZhang2008). 1. ^ [***a***](#cite_ref-FOOTNOTELajoieBertrandEl-Mabrouk200796_2-0) [***b***](#cite_ref-FOOTNOTELajoieBertrandEl-Mabrouk200796_2-1) [***c***](#cite_ref-FOOTNOTELajoieBertrandEl-Mabrouk200796_2-2) [Lajoie, Bertrand & El-Mabrouk 2007](#CITEREFLajoieBertrandEl-Mabrouk2007), p. 96. 1. **[^](#cite_ref-Lodish_3-0)** Lodish, Harvey; Arnold Berk; Chris Kaiser; Monty Krieger; Anthony Bretscher; Hidde Ploegh; Angelika Amon; Matthew Scott (2013). "Genes, Genomics, and Chromosomes". In Beth McHenry (ed.). *Molecular Cell Biology* (7 ed.). New York: W.H. Freeman Company. pp. 227–230. [ISBN](/source/ISBN_(identifier)) [978-1-4292-3413-9](https://en.wikipedia.org/wiki/Special:BookSources/978-1-4292-3413-9). 1. **[^](#cite_ref-FOOTNOTEBarkerBauteLiu2012157_4-0)** [Barker, Baute & Liu 2012](#CITEREFBarkerBauteLiu2012), p. 157. ## References - Barker, Michael S.; Baute, Gregory J.; Liu, Shao-Lun (5 March 2012). "Duplications and Turnover in Plant Genomes". In Wendel, Jonathan F.; Greilhuber, Johann; Dolezel, Jaroslav; et al. (eds.). *Plant Genome Diversity Volume 1: Plant Genomes, their Residents, and their Evolutionary Dynamics*. Plant Genome Diversity. Vol. 1. Springer Science & Business Media. pp. 155–169. [doi](/source/Doi_(identifier)):[10.1007/978-3-7091-1130-7_11](https://doi.org/10.1007%2F978-3-7091-1130-7_11). [ISBN](/source/ISBN_(identifier)) [978-3-7091-1130-7](https://en.wikipedia.org/wiki/Special:BookSources/978-3-7091-1130-7). - Pan, Deng; Zhang, Liqing (2008). ["Tandemly arrayed genes in vertebrate genomes"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2547482). *International Journal of Genomics*. **2008** 545269. Hindawi Publishing Corporation. [doi](/source/Doi_(identifier)):[10.1155/2008/545269](https://doi.org/10.1155%2F2008%2F545269). [PMC](/source/PMC_(identifier)) [2547482](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2547482). [PMID](/source/PMID_(identifier)) [18815629](https://pubmed.ncbi.nlm.nih.gov/18815629). - Lajoie, Mathieu; Bertrand, Denis; El-Mabrouk, Nadia (16–18 September 2007). "Evolution of tandemly-arrayed genes in multiple species". In Tesler, Glenn; Durand, Dannie (eds.). *Comparative Genomics: RECOMB 2007, International Workshop, RECOMB-CG 2007, San Diego, CA, USA, September 16–18, 2007, Proceedings*. RECOMB 2007, International Workshop, RECOMB-CG 2007. Lecture Notes in Bioinformatics. Vol. 4751. [San Diego](/source/San_Diego): Springer Science & Business Media. pp. 96–107. [ISBN](/source/ISBN_(identifier)) [978-3-540-74959-2](https://en.wikipedia.org/wiki/Special:BookSources/978-3-540-74959-2). [ISSN](/source/ISSN_(identifier)) [0302-9743](https://search.worldcat.org/issn/0302-9743). v t e Genetics: repeated sequence, transposon, gene duplication Repeatome Repeated sequence Tandem repeats Satellite DNA Variable number tandem repeat/Minisatellite Short tandem repeat/Microsatellite (Trinucleotide repeat disorders) Macrosatellite Interspersed repeat Gene conversion Retrotransposon DNA transposon Polinton Helitron Other Inverted repeat Direct repeat Transposon Retrotransposon SINEs Alu sequence MIR LINEs LINE1 LINE2 LTRs HERV MER4 retroposon DNA transposon Academ Crypton Dada EnSpm/CACTA Ginger1 Ginger2 Harbinger hAT Helitron IS3EU ISL2EU Kolobok Tc1/mariner Merlin MuDR Novosib P element PiggyBac Polinton Sola Transib Zator Zisupton Gene duplication Gene amplification Tandemly arrayed genes Ribosomal DNA Gene family Gene cluster Pseudogene See also Genomic island Pathogenicity island Symbiosis island Low copy repeats CRISPR Telomere Protein tandem repeats This genetics article is a stub. 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