title: Effects of cis-trans viability selection on some two-locus models.
abstract: Most analyses of two-locus viability models have assumed that the fitness of double heterozygotes are the same whether in the cis or trans configuration. This assumption is unlikely to hold for polymorphic sites within the same locus. We examine the quantitative and qualitative effects of incorporating cis-trans viability differences into a number of deterministic two-locus models. A new result is the finding that two asymmetric equilibria with similar levels of linkage disequilibrium, but different gene frequencies, may arise in quite realistic biological models. The general, and most important, conclusion is that high levels of linkage disequilibrium may be generated by very small selective differences in cis and trans. Polymorphic sites that interact selectively are expected to show high levels of linkage disequilibrium. Conversely, if two polymorphic sites within a gene are found to be in linkage equilibrium, it is likely that one or both are selectively neutral.
authors.affiliation: Department of Biological Sciences, Stanford University, California 94305-5020, USA.
authors.forename: M
authors.initials: M
authors.lastname: Nordborg
authors.forename: I R
authors.initials: IR
authors.lastname: Franklin
authors.forename: M W
authors.initials: MW
authors.lastname: Feldman
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D004330:Drosophila / Q000235:genetics; D005816:Genetic Complementation Test; D014644:Genetic Variation; D015810:Linkage Disequilibrium; D008957:Models, Genetic; D011110:Polymorphism, Genetic / Q000235:genetics