title: Molecular basis of the copulatory plug polymorphism in Caenorhabditis elegans.
abstract: Heritable variation is the raw material for evolutionary change, and understanding its genetic basis is one of the central problems in modern biology. We investigated the genetic basis of a classic phenotypic dimorphism in the nematode Caenorhabditis elegans. Males from many natural isolates deposit a copulatory plug after mating, whereas males from other natural isolates?including the standard wild-type strain (N2 Bristol) that is used in most research laboratories?do not deposit plugs. The copulatory plug is a gelatinous mass that covers the hermaphrodite vulva, and its deposition decreases the mating success of subsequent males. We show that the plugging polymorphism results from the insertion of a retrotransposon into an exon of a novel mucin-like gene, plg-1, whose product is a major structural component of the copulatory plug. The gene is expressed in a subset of secretory cells of the male somatic gonad, and its loss has no evident effects beyond the loss of male mate-guarding. Although C. elegans descends from an obligate-outcrossing, male?female ancestor, it occurs primarily as self-fertilizing hermaphrodites. The reduced selection on male?male competition associated with the origin of hermaphroditism may have permitted the global spread of a loss-of-function mutation with restricted pleiotropy.
authors.affiliation: Department of Biology, Bowdoin College, 6500 College Station, Brunswick, Maine 04011, USA. mpalopol@bowdoin.edu
authors.forename: Michael F
authors.initials: MF
authors.lastname: Palopoli
authors.forename: Matthew V
authors.initials: MV
authors.lastname: Rockman
authors.forename: Aye
authors.initials: A
authors.lastname: TinMaung
authors.forename: Camden
authors.initials: C
authors.lastname: Ramsay
authors.forename: Stephen
authors.initials: S
authors.lastname: Curwen
authors.forename: Andrea
authors.initials: A
authors.lastname: Aduna
authors.forename: Jason
authors.initials: J
authors.lastname: Laurita
authors.forename: Leonid
authors.initials: L
authors.lastname: Kruglyak
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000502:physiology; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003307:Copulation; D012734:Disorders of Sex Development / Q000235:genetics; D005786:Gene Expression Regulation; D008297:Male; D009077:Mucins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011110:Polymorphism, Genetic; D018626:Retroelements / Q000235:genetics
chemical_list: D029742:Caenorhabditis elegans Proteins; D009077:Mucins; D018626:Retroelements; C531102:plg-1 protein, C elegans