title: Widespread genetic incompatibility in C. elegans maintained by balancing selection.
abstract: Natural selection is expected to eliminate genetic incompatibilities from interbreeding populations. We have discovered a globally distributed incompatibility in the primarily selfing species Caenorhabditis elegans that has been maintained despite its negative consequences for fitness. Embryos homozygous for a naturally occurring deletion of the zygotically acting gene zeel-1 arrest if their sperm parent carries an incompatible allele of a second, paternal-effect locus, peel-1. The two interacting loci are tightly linked, with incompatible alleles occurring in linkage disequilibrium in two common haplotypes. These haplotypes exhibit elevated sequence divergence, and population genetic analyses of this region indicate that natural selection is preserving both haplotypes in the population. Our data suggest that long-term maintenance of a balanced polymorphism has permitted the incompatibility to persist despite gene flow across the rest of the genome.
authors.affiliation: Lewis-Sigler Institute for Integrative Genomics and Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA. hseidel@princeton.edu
authors.forename: Hannah S
authors.initials: HS
authors.lastname: Seidel
authors.forename: Matthew V
authors.initials: MV
authors.lastname: Rockman
authors.forename: Leonid
authors.initials: L
authors.lastname: Kruglyak
mesh_terms: D000483:Alleles; D000818:Animals; D030801:Animals, Genetically Modified; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics*; D003001:Cloning, Molecular; D003433:Crosses, Genetic; D012734:Disorders of Sex Development; D004625:Embryo, Nonmammalian / Q000502:physiology; D047108:Embryonic Development; D051456:Gene Flow; D017238:Genes, Helminth; D008040:Genetic Linkage; D049751:Genome, Helminth; D006239:Haplotypes; D015810:Linkage Disequilibrium; D008297:Male; D008969:Molecular Sequence Data; D019683:Penetrance; D020641:Polymorphism, Single Nucleotide; D012641:Selection, Genetic