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CAN GENE FLOW PREVENT REINFORCEMENT?
Author(s) -
Sanderson Neil
Publication year - 1989
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.1989.tb02570.x
Subject(s) - reinforcement , cline (biology) , selection (genetic algorithm) , biology , hybrid , gene flow , allele , reproductive isolation , genetics , evolutionary biology , gene , computer science , population , engineering , structural engineering , artificial intelligence , genetic variation , botany , demography , sociology
A model of reinforcement in a hybrid zone is developed in which an allele causing reinforcement may only be favored in the center of the hybrid zone and is selected against elsewhere. When reinforcement is favored only in the hybrid zone, the swamping effect of gene flow severely impedes the evolution of reinforcement: reinforcement can only occur when β < sγ 2 /4 ( s is selection against hybrids, γ is the strength of reinforcement, and β is the strength of selection against reinforcement). Although the region in which reinforcement can occur is narrower when selection against hybrids is stronger, strong selection is still more likely to be reinforced despite the effects of gene flow. Another modifier is considered which reduces postmating isolation. The conditions for increase in frequency of this modifier reduce to the same conditions as those for the reinforcing allele. Both kinds of modification reduce the strength of selection and, therefore, cause the cline to widen. Reinforcement causes an increase in premating isolation between races, while modification of selection reduces postmating isolation.