selection pressure

Allele-proportion change rate depends on allele reproductive advantage {selection pressure}| and on whether allele is recessive or dominant.

variation

Population allele ratio changes by heterozygote superiority, environmental heterogeneity, cycles, agonistic or antagonistic gene linkages, and homozygote selection.

balancing

Natural selection can maintain allele ratios {stabilizing selection} {balancing selection} to maintain variation. Balancing selection happens in large, non-isolated populations with alleles that are neither dominant nor recessive.

directional

Natural selection can change allele ratios {directional selection} {purifying selection} to reduce variation. Directional selection can happen by genetic drift or inbreeding in small isolated populations.

Whole Section in One File

4-Genetics-Allele-Population Genetics

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Technical Information

Date Modified: 2022.0224