Concerted Evolution


Concerted evolution is a genetic process by which repetitive deoxyribonucleic acid (DNA) sequences are homogenized so that the sequence of a given multigene family within a species shares much higher sequence identity than that of the homologous gene family between two different species. Concerted evolution occurs in all living organisms, from bacteria to humans. DNA recombination mechanisms, especially unequal crossover and gene conversion, are responsible for concerted evolution.

Keywords: molecular evolution; repetitive sequence; multigene family; sequence homogenization; DNA recombination; gene conversion

Figure 1.

Structures of multigene families undergoing concerted evolution. (a) Structure of human ribosomal DNA (rDNA) arrays. Genic regions are shown as red rectangles and sequences flanking the tandem arrays as hatched rectangles. Other sequence elements such as Cytosine–Thymine‐like (CT dinucleotide) microsatellites and CDC27 pseudogene are also shown. ITS, internal transcribed spacer; IGS, intergenic spacers; NTS, nontranscribed spacer and ETS, external transcribed spacer. The repeat unit is drawn to scale based on data from GenBank entry U13369. (b) Structure of human U2 small nuclear RNA (snRNA) repeat and tandem array. (c) Array structure of yeast Saccharomyces cerevisiae rDNA. (d) Operon structure of Escherichia coli (rRNA).

Figure 2.

Mechanism of concerted evolution of tandemly repeated genes. Tandem arrays on two different chromosomes are shown. Species‐specific mutation (dot) may arise after speciation, which may either be eliminated or spread to all copies in a tandem array by intrachromosomal recombination such as intrachromatid conversion and/or unequal sister chromatid exchange (USCE). Gene conversion between two homologues leads to spread of the mutation and eventual homogenization within a species. Adapted from Liao .



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Further Reading

Carmon A, Wilkin M, Hassan J, Baron M and MacIntyre R (2007) Concerted evolution within the Drosophila dumpy gene. Genetics 176: 309–325.

Ogoh K and Ohmiya Y (2007) Concerted evolution of duplicated control regions within an ostracod mitochondrial genome. Molecular Biology and Evolution 24: 74–78.

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Stewart FJ and Cavanaugh CM (2007) Intragenomic variation and evolution of the internal transcribed spacer of the rRNA operon in bacteria. Journal of Molecular Evolution 65: 44–67.

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How to Cite close
Liao, Daiqing(Mar 2008) Concerted Evolution. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0005132.pub2]