title: Cytoplasmic-Nuclear Incompatibility Between Wild Isolates ofCaenorhabditis nouraguensis.
abstract: How species arise is a fundamental question in biology. Species can be defined as populations of interbreeding individuals that are reproductively isolated from other such populations. Therefore, understanding how reproductive barriers evolve between populations is essential for understanding the process of speciation. Hybrid incompatibility (for example, hybrid sterility or lethality) is a common and strong reproductive barrier in nature. Here we report a lethal incompatibility between two wild isolates of the nematodeCaenorhabditis nouraguensisHybrid inviability results from the incompatibility between a maternally inherited cytoplasmic factor from each strain and a recessive nuclear locus from the other. We have excluded the possibility that maternally inherited endosymbiotic bacteria cause the incompatibility by treating both strains with tetracycline and show that hybrid death is unaffected. Furthermore, cytoplasmic-nuclear incompatibility commonly occurs between other wild isolates, indicating that this is a significant reproductive barrier withinC. nouraguensisWe hypothesize that the maternally inherited cytoplasmic factor is the mitochondrial genome and that mitochondrial dysfunction underlies hybrid death. This system has the potential to shed light on the dynamics of divergent mitochondrial-nuclear coevolution and its role in promoting speciation.
authors.affiliation: Molecular and Cellular Biology Program, University of Washington, Seattle, Washington 98195.|Department of Biochemistry, University of Washington, Seattle, Washington 98195.
authors.forename: Piero
authors.initials: P
authors.lastname: Lamelza
authors.affiliation: Molecular and Cellular Biology Program, University of Washington, Seattle, Washington 98195 mailion@uw.edu.|Department of Biochemistry, University of Washington, Seattle, Washington 98195.
authors.forename: Michael
authors.identifier: 0000-0002-8070-1362
authors.initials: M
authors.lastname: Ailion
mesh_terms: D000483:Alleles; D000818:Animals; D001419:Bacteria / Q000235:genetics; D002107:Caenorhabditis / Q000196:embryology / Q000235:genetics* / Q000302:isolation & purification* / Q000382:microbiology; D002467:Cell Nucleus / Q000235:genetics*; D002875:Chromosomes / Q000235:genetics; D020964:Embryo Loss / Q000235:genetics; D005260:Female; D056426:Genetic Loci; D006824:Hybridization, Genetic; D008297:Male; D008957:Models, Genetic; D013559:Symbiosis
keywords: Caenorhabditis; cytoplasmic–nuclear incompatibility; hybrid incompatibility; mitochondria; speciation