heterozygote advantage
Evolutionary phenomenon where carriers of one copy of a genetic mutation have selective advantages, explaining persistence of harmful alleles in populations.
Full Definition
Heterozygote advantage occurs when individuals who carry one copy of a genetic mutation (heterozygotes) have survival or reproductive advantages compared to those with two normal copies (homozygotes). Classic examples include sickle cell trait providing malaria resistance and cystic fibrosis carriers having protection against cholera. This phenomenon explains why harmful recessive alleles persist in human populations at relatively high frequencies. In reproductive genetics, understanding heterozygote advantage helps explain carrier frequency patterns and informs population screening strategies for various ethnic groups.
Usage
Usage note: Use as compound noun; avoid hyphenating unless used as adjective modifier.
In Context
- "The high frequency of beta-thalassemia carriers in Mediterranean populations reflects heterozygote advantage against malaria." — Population genetics discussion
- "Heterozygote advantage may explain the persistence of Tay-Sachs carriers in certain ethnic groups." — Genetic counseling education