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.


Last Editorial Review: 6/14/2012

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