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 stabilizing 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 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

References

  1. ↑ Loewe L (2008). "Negative selection". Nature Education. 1 (1): 59.
  2. ↑ Tien NS, Sabelis MW, Egas M (March 2015). "Inbreeding depression and purging in a haplodiploid: gender-related effects". Heredity. 114 (3): 327–32. doi:10.1038/hdy.2014.106. PMC 4815584. PMID 25407077.
  3. ↑ Gulisija D, Crow JF (May 2007). "Inferring purging from pedigree data". Evolution; International Journal of Organic Evolution. 61 (5): 1043–51. doi:10.1111/j.1558-5646.2007.00088.x. PMID 17492959.
  4. ↑ Charlesworth B, Morgan MT, Charlesworth D (August 1993). "The effect of deleterious mutations on neutral molecular variation". Genetics. 134 (4): 1289–303. PMC 1205596. PMID 8375663.
  5. ↑ Hudson RR, Kaplan NL (December 1995). "Deleterious background selection with recombination". Genetics. 141 (4): 1605–17. PMC 1206891. PMID 8601498.
  6. ↑ Glémin S (December 2003). "How are deleterious mutations purged? Drift versus nonrandom mating". Evolution; International Journal of Organic Evolution. 57 (12): 2678–87. PMID 14761049.
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