genetic variance A portion of phenotypic variance that results from the varying genotypes of the individuals in a population. Together with the environmental variance, it adds up to the total phenotypic variance observed among individuals in a population. When a particular phenotypic character is controlled by more than one gene, the genetic variance (V_G) is equal V_D + V_I + V_A, where V_D is the variance of components owing to the dominance of alleles at a particular locus, V_I is the sum of the epistatic (see epistasis) interactions at different loci, and V_A is the additive genetic variance determined by the cumulative effects of alleles within and among loci (e.g. the resemblance of offspring to their parents is due to additive genetic variance). The phenotypic variance (V_P) is equal to the sum of the environmental variance (V_E) and V_G and the heritability of a particular trait is given by V_A/V_P. (V is sometimes written as s².)

genetic variance The portion of phenotypic variance that results from the varying genotypes of the individuals in a population. Together with the environmental variance, it adds up to the total phenotypic variance observed amongst individuals in a population.

genetic variance A portion of phenotypic variance that results from the varying genotypes of the individuals in a population. Together with the environmental variance, it adds up to the total phenotypic variance observed among individuals in a population.