advantageous heterozygosity
Quick Summary
Advantageous heterozygosity occurs when a heterozygote organism possesses a higher fitness than either of its homozygous parents. This phenomenon is a form of natural selection where having two different alleles for a trait provides a survival or reproductive advantage in certain environments.12
A classic example is the sickle cell trait. Individuals who are homozygous for the sickle cell allele often suffer from severe anemia. However, heterozygotes for this trait (carrying one normal hemoglobin allele and one sickle cell allele) exhibit a resistance to malaria, making them more fit in malaria-prone regions. This resistance outweighs the negative effects of the sickle cell allele in heterozygotes, leading to the maintenance of the allele within populations.23
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