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Related to genetic polymorphism: Single nucleotide polymorphism
the ability to exist in several different forms.
balanced polymorphism an equilibrium mixture of homozygotes and heterozygotes maintained by natural selection against both homozygotes.
genetic polymorphism the occurrence together in the same population of two or more genetically determined phenotypes in such proportions that the rarest of them cannot be maintained merely by recurrent mutation.
the occurrence in the same population of multiple discrete alletic states of which at least two have high frequency (conventionally of 1% or more).
the recurrence within a population of two or more discontinuous genetic variants of a specific trait in such proportions that they cannot be maintained simply by mutation. Examples include the sickle cell trait, the Rh factor, and the blood groups. Compare balanced polymorphism.