Medical Definition of Polymorphism
Polymorphism: A variation in the DNA that is too common to be due merely to new mutation. A polymorphism must have a frequency of at least 1% in the population.
Examples of polymorphisms include the genes for sickle cell disease, thalassemia and G6PD deficiency. These genes are widely believed to offer an advantage against malaria.Source: MedTerms™ Medical Dictionary
Last Editorial Review: 1/24/2017