Additive genetic effects

Genetic effects are broadly divided into two categories: additive and non-additive. Additive genetic effects occur where expression of more than one gene contributes to <a href="/facts/Phenotype/vxWXKGLj">phenotype</a> (or where <a href="/facts/Allele/8FxCS9KA">alleles</a> of a <a href="/facts/Zygosity/XzEJ5gPp">heterozygous</a> gene both contribute), and the phenotypic expression of these gene(s) can be said to be the sum of these contributions.
Non-additive effects involve <a href="/facts/Dominance_(genetics)/DsvtPyQU">dominance</a> or <a href="/facts/Epistasis/bJAJL90w">epistasis</a>, and cause outcomes that are not a sum of the contribution of the genes involved.
Additive genetic effects are singularly important with regard to <a href="/facts/Complex_traits/l6HY9lPG">quantitative traits</a>, as the sum of these effects informs the placement of a trait on the spectrum of possible outcomes. Quantitative traits are commonly polygenic (resulting from the effects of more than one <a href="/facts/Locus_(genetics)/JcIT8wLm">locus</a>).

Additive genetic effects open-in-new

Additive genetic effects