In population genetics, directional selection (sometimes referred to as positive selection) occurs when natural selection favors a single allele and therefore allele frequency continuously shifts in one direction. It stands in contrast to balancing selection where selection may favor multiple alleles, or stabilizing selection which removes deleterious mutations from a population. Directional selection is a particular mode or mechanism of natural selection.

See alsoEdit

• Stabilizing selection
• Disruptive selection
• Balancing selection