Biology:Negative selection (natural selection)
In natural selection, negative selection[1] or purifying selection is the selective removal of alleles that are deleterious. This can result in stabilising selection through the purging of deleterious genetic polymorphisms that arise through random mutations.[2][3]
Purging of deleterious alleles can be achieved on the population genetics level, with as little as a single point mutation being the unit of selection. In such a case, carriers of the harmful point mutation have fewer offspring each generation, reducing the frequency of the mutation in the gene pool.
In the case of strong negative selection on a locus, the purging of deleterious variants will result in the occasional removal of linked variation, producing a decrease in the level of variation surrounding the locus under selection. The incidental purging of non-deleterious alleles due to such spatial proximity to deleterious alleles is called background selection.[4] This effect increases with lower mutation rate but decreases with higher recombination rate.[5]
Purifying selection can be split into purging by non-random mating (assortative mating) and purging by genetic drift. Purging by genetic drift can remove primarily deeply recessive alleles, whereas natural selection can remove any type of deleterious alleles.[6]
See also
- Assortative mating
- Balancing selection
- Directional selection
- Disruptive selection
- Dysgenics
- Fluctuating selection
- Genetic purging
- Koinophilia
- Mutation–selection balance
- Stabilizing selection
References
- ↑ Loewe, Laurence (2008). "Negative selection". Nature Education 1 (1): 59. https://www.nature.com/scitable/topicpage/Negative-Selection-1136.
- ↑ "Inbreeding depression and purging in a haplodiploid: gender-related effects". Heredity 114 (3): 327–32. March 2015. doi:10.1038/hdy.2014.106. PMID 25407077.
- ↑ "Inferring purging from pedigree data". Evolution; International Journal of Organic Evolution 61 (5): 1043–51. May 2007. doi:10.1111/j.1558-5646.2007.00088.x. PMID 17492959.
- ↑ "The effect of deleterious mutations on neutral molecular variation". Genetics 134 (4): 1289–303. August 1993. doi:10.1093/genetics/134.4.1289. PMID 8375663.
- ↑ "Deleterious background selection with recombination". Genetics 141 (4): 1605–17. December 1995. doi:10.1093/genetics/141.4.1605. PMID 8601498.
- ↑ "How are deleterious mutations purged? Drift versus nonrandom mating". Evolution; International Journal of Organic Evolution 57 (12): 2678–87. December 2003. doi:10.1111/j.0014-3820.2003.tb01512.x. PMID 14761049.
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