Recombination hotspot

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Recombination hotspots are regions in a genome that exhibit elevated rates of recombination, relative to a neutral expectation. The peak recombination rate within hotspots can be hundreds or thousands of times that of the surrounding region.[1] The PRDM9 protein is suspected to be a cause of hotspots in mammals.[2] All hotspots so far characterized share similar morphology and are approximately 1.5 to 2.0 kb in width, which suggests a common causal process. Furthermore, recent studies have used patterns in linkage disequilibrium to identify over 25,000 hotspots in the human genome,[3] suggesting that hotspots are a ubiquitous feature of the genome. In humans, the average number of crossover recombination events per hotspot is one crossover per 1,300 meioses, and the most extreme hotspot has a crossover frequency of one per 110 meioses.[4]

The large number of recombination hotspots is consistent with a wide distribution of sites. These sites may be particularly vulnerable to naturally occurring (un-programmed) DNA damages that are subject to recombinational repair, and may also include specific sites where a crossover is needed to promote synapsis of the paired homologous chromosomes.[5]

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  1. ^ Jeffreys AJ, Kauppi L, Neumann R (October 2001). "Intensely punctate meiotic recombination in the class II region of the major histocompatibility complex". Nat. Genet. 29 (2): 217–22. doi:10.1038/ng1001-217. PMID 11586303. 
  2. ^ Hochwagen A, Marais GA (March 2010). "Meiosis: a PRDM9 guide to the hotspots of recombination". Curr. Biol. 20 (6): R271–4. doi:10.1016/j.cub.2010.01.048. PMID 20334833. 
  3. ^ Myers S, Bottolo L, Freeman C, McVean G, Donnelly P (October 2005). "A fine-scale map of recombination rates and hotspots across the human genome". Science 310 (5746): 321–4. doi:10.1126/science.1117196. PMID 16224025. 
  4. ^ Myers S, Spencer CC, Auton A, et al. (August 2006). "The distribution and causes of meiotic recombination in the human genome". Biochem. Soc. Trans. 34 (Pt 4): 526–30. doi:10.1042/BST0340526. PMID 16856851. 
  5. ^ Harris Bernstein, Carol Bernstein and Richard E. Michod (2011). Meiosis as an Evolutionary Adaptation for DNA Repair. Chapter 19 in DNA Repair. Inna Kruman editor. InTech Open Publisher. DOI: 10.5772/25117 http://www.intechopen.com/books/dna-repair/meiosis-as-an-evolutionary-adaptation-for-dna-repair