Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
Pleiotropy refers to a phenomenon in genetics where a single gene influences multiple phenotypic traits or characteristics. Essentially, one gene has effects on multiple aspects of an organism's phenotype.
Related terms
Polygenic Inheritance: Polygenic inheritance is when multiple genes contribute to the expression of a single trait. Unlike pleiotropy, which involves one gene affecting multiple traits, polygenic inheritance involves several genes influencing one specific trait.
The genotype refers to the genetic makeup or combination of alleles that an organism possesses. It determines the potential range of phenotypes that can be expressed under varying environmental conditions.
The phenotype is the observable physical or biochemical characteristics of an organism resulting from its genotype interacting with its environment. It includes traits such as eye color, height, and behavior.