Inference from clines stabilized by frequency-dependent selection Journal Article

Author(s): Mallet, James L; Barton, Nicholas H
Article Title: Inference from clines stabilized by frequency-dependent selection
Abstract: Frequency-dependent selection against rare forms can maintain clines. For weak selection, s, in simple linear models of frequency-dependence, single locus clines are stabilized with a maximum slope of between {complex}s/{complex}8 {sigma} and {complex}s/{complex}12 {delta}, where {sigma} is the dispersal distance. These clines are similar to those maintained by heterozygote disadvantage. Using computer simulations, the weak-selection analytical results are extended to higher selection pressures with up to three unlinked genes. Graphs are used to display the effect of selection, migration, dominance, and number of loci on cline widths, speeds of cline movements, two-way gametic correlations (``linkage disequilibria''), and heterozygote deficits. The effects of changing the order of reproduction, migration, and selection, are also briefly explored. Epistasis can also maintain tension zones. We show that epistatic selection is similar in its effects to frequency-dependent selection, except that the disequilibria produced in the zone will be higher for a given level of selection. If selection consists of a mixture of frequency-dependence and epistasis, as is likely in nature, the error made in estimating selection is usually less than twofold. From the graphs, selection and migration can be estimated using knowledge of the dominance and number of genes, of gene frequences and of gametic correlations from a hybrid zone.
Keywords: Selection, Genetic; Epistasis, Genetic; Hybridization, Genetic; Models, Genetic; Computer Simulation; Genetics, Population; Emigration and Immigration; Gene Frequency; Genes, Dominant; Heterozygote; Reproduction; Genetic Linkage
Journal Title: Genetics
Volume: 122
Issue 4
ISSN: 0016-6731
Publisher: Genetics Society of America  
Date Published: 1989-08-01
Start Page: 967
End Page: 976
Open access: yes (repository)