genetic polymorphism

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genetic polymorphism An occurrence in a population of 2 or more genotypes in frequencies that cannot be accounted for by recurrent mutation. Such occurrences are generally long-term. Genetic polymorphism may be balanced (such that allele frequencies are in equilibrium with one another at a given locus), or transient (such that a mutation is spreading through the population in a constant direction). In the former case, the different alleles may be maintained by different environmental conditions (in space or time), one being favoured under one set of circumstances and another under another set; or a heterozygous genotype may be in some way superior to the genotypes that are homozygous at that locus; this is termed a ‘heterozygous advantage’.

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genetic polymorphism

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genetic polymorphism