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Submitted to: Campylobacter Ecology and Evolution
Publication Type: Book / Chapter Publication Acceptance Date: 4/3/2013 Publication Date: 4/1/2014 Citation: Meinersmann, R.J. 2014. Concerted evolution in Campylobacter jejuni and Campylobacter coli. Campylobacter Ecology and Evolution. S.K. Sheppard and G. Meric, ed. Caister Academic Press, Norfolk, UK. Chapter 4:33-41. Interpretive Summary: It is common for some genes to be present as multiple copies in an organism’s genome. Multiple copies of a gene are inherently unstable because the similarities allow the copies to interact with each other in a way that can cause the replication system to jump across a copy resulting in its loss. However, there are some genes that are beneficial to have in multiple copies, such as the ribosomes that are needed to put together proteins in the cell. It turns out that the multiple copy genes are more similar to each other within a single cell than would be predicted based on the amount of differences seen between cells. This phenomenon is called “concerted evolution.” Researchers need to know the effects of concerted evolution on genes they are studying in order to accurately understand bacterial ancestry and to be aware of possible biological effects of concerted evolution on the genes of interest. This manuscript is a review article intended to outline the known effects of concerted evolution in the foodborne pathogens Campylobacter jejuni and C. coli. Three sets of multiple copy genes have been studied in Campylobacter to date: the 23S ribosomal gene, the flagellin genes, and the ribosomal intergenic sequence. Technical Abstract: Concerted evolution is the phenomenon in which multiple copies of genes maintain sequence similarity in a single individual while the genes continue to diverge between individuals. Concerted evolution has been described in Campylobacter jejuni and C. coli for the pair of flagellin genes, which are notable for their diversity, the 23S ribosomal RNA genes, which are notable for the degree that they are conserved, and for the portion of the ribosomal operon between the 16S and 23S genes. The evidence for concerted evolution is presented and the biological implications are discussed in this review. An interesting case is the concerted evolution of the 23S rRNA genes that is needed to rapidly become resistant to macrolides. Understanding which genes are affected by concerted evolution will allow proper assessment of probable phylogenetic distortions that will be seen with such genes. |
