Additive genes are genes that code for the same function that has a wide range of phenotypes. This allows for a wide ranges of phenotypes based on genetic coding.1 Additive genes are independent of other genes and when coupled with non-additive genes, are the result of genetic variance.2


4. Example of additive genetic variance.

Additive genes are related to epistasis because they contribute to epistatic effects - the presence of an additive gene can change the way other alleles act.2

The environment can have an effect on additive genes - stress can change additive genetic variance and can increase heritability.3

1. Biology Online (2005). Additive Genes. Retrieved from

2. Show, Carson (2013). Heritability and Additive Genetic Variance. Retrieved from

3. Blows, M and Sokolowski, M (1995). The Expression of Additive and Nonadditive Genetic Variation Under Stress. The Genetics Society of America. Retrieved from

4. Additive Trait (n.d.). Retrieved from