出典:Wiktionary
出典:『Wiktionary』 (2025/11/27 20:52 UTC 版)
directional selection (plural directional selections)
出典:Wikipedia
出典:『Wikipedia』 (2011/06/28 22:37 UTC 版)
In population genetics, directional selection is a mode of natural selection in which a single phenotype is favored, causing the allele frequency to continuously shift in one direction. Under directional selection, the advantageous allele increases in frequency independently of its dominance relative to other alleles; that is, even if the advantageous allele is recessive, it will eventually become fixed. Directional selection stands in contrast to balancing selection where selection may favor multiple alleles, and is the same as purifying selection which removes deleterious mutations from a population.