Additive genetics

Additive genetics are genes that add together to create an effect on a trait. It happens if multiple genes affect the same trait or phenotype. This can be genes for height or genes for if someone gets a disease. For example, one gene might cause someone to be a millimeter taller. A different gene might cause someone to be two millimeters taller. Since the effect of the genes add together, having both of these genes would result in being three (one plus two) millimeters taller.

When genes do not add together, it is called dominance or epistasis, which can be important for Menedelian (single-gene) diseases. Sometimes, even when there are some dominant genes, additive genetics can be more important.

Complex traits are usually determined by many genes which add together. For example, dominance is not important compared to additive genetics for some traits, including height, weight, blood pressure, and heart rate.

 Related pages 
 Quantitative genetics

 References 

Category:Genetics