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The opposing effects of genetic drift and Haldane's sieve on floral‐morph frequencies in tristylous metapopulations
Author(s) -
Roux Camille,
Pannell John R.
Publication year - 2019
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.16187
Subject(s) - metapopulation , biology , allele , genetic drift , genetics , evolutionary biology , population , selection (genetic algorithm) , context (archaeology) , frequency dependent selection , heterozygote advantage , allele frequency , balancing selection , genetic variation , biological dispersal , gene , demography , paleontology , artificial intelligence , sociology , computer science
Summary Tristyly is a genetic floral polymorphism in which three floral morphs are maintained at equal frequencies by negative frequency‐dependent selection on alleles at two interacting loci. Because dominant alleles at these loci are maintained at a lower frequency than their recessive counterparts, they are more likely to be lost by founder events and genetic drift. Here we examine the hypothesis that dominant alleles under negative frequency‐dependent selection should also be more likely to re‐invade populations than recessive alleles, due to Haldane's Sieve, because recessive alleles not expressed in a heterozygote state cannot benefit from positive selection when rare. We used computer simulations of tristylous metapopulations to verify that Haldane's Sieve acting on migrants into occupied demes can indeed reverse the bias in allele frequencies expected for small single tristylous populations, particularly in situations of rapid population growth following colonisation. This effect is manifest both locally and at the metapopulation level. Our study illustrates the potential effect of Haldane's Sieve in the novel context of an iconic plant sexual‐system polymorphism under the influence of metapopulation dynamics.