title: Genetic control of contagious asexuality in the pea aphid.
abstract: Although evolutionary transitions from sexual to asexual reproduction are frequent in eukaryotes, the genetic bases of such shifts toward asexuality remain largely unknown. We addressed this issue in an aphid species where both sexual and obligate asexual lineages coexist in natural populations. These sexual and asexual lineages may occasionally interbreed because some asexual lineages maintain a residual production of males potentially able to mate with the females produced by sexual lineages. Hence, this species is an ideal model to study the genetic basis of the loss of sexual reproduction with quantitative genetic and population genomic approaches. Our analysis of the co-segregation of ∼ 300 molecular markers and reproductive phenotype in experimental crosses pinpointed an X-linked region controlling obligate asexuality, this state of character being recessive. A population genetic analysis (>400-marker genome scan) on wild sexual and asexual genotypes from geographically distant populations under divergent selection for reproductive strategies detected a strong signature of divergent selection in the genomic region identified by the experimental crosses. These population genetic data confirm the implication of the candidate region in the control of reproductive mode in wild populations originating from 700 km apart. Patterns of genetic differentiation along chromosomes suggest bidirectional gene flow between populations with distinct reproductive modes, supporting contagious asexuality as a prevailing route to permanent parthenogenesis in pea aphids. This genetic system provides new insights into the mechanisms of coexistence of sexual and asexual aphid lineages.
authors.affiliation: INRA, UMR1349, Institute of Genetics, Environment and Plant Protection, Domaine de la Motte, Le Rheu, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Jaquiéry
authors.affiliation: INRA, UMR1349, Institute of Genetics, Environment and Plant Protection, Domaine de la Motte, Le Rheu, France.
authors.forename: Solenn
authors.initials: S
authors.lastname: Stoeckel
authors.affiliation: INRA, UMR1349, Institute of Genetics, Environment and Plant Protection, Domaine de la Motte, Le Rheu, France.
authors.forename: Chloé
authors.initials: C
authors.lastname: Larose
authors.affiliation: INRA, UMR1349, Institute of Genetics, Environment and Plant Protection, Domaine de la Motte, Le Rheu, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Nouhaud
authors.affiliation: INRA, UMR1349, Institute of Genetics, Environment and Plant Protection, Domaine de la Motte, Le Rheu, France.
authors.forename: Claude
authors.initials: C
authors.lastname: Rispe
authors.affiliation: INRA, UMR1349, Institute of Genetics, Environment and Plant Protection, Domaine de la Motte, Le Rheu, France.
authors.forename: Lucie
authors.initials: L
authors.lastname: Mieuzet
authors.affiliation: INRA, UMR1349, Institute of Genetics, Environment and Plant Protection, Domaine de la Motte, Le Rheu, France.
authors.forename: Joël
authors.initials: J
authors.lastname: Bonhomme
authors.affiliation: INRA, UMR1349, Institute of Genetics, Environment and Plant Protection, Domaine de la Motte, Le Rheu, France.
authors.forename: Frédérique
authors.initials: F
authors.lastname: Mahéo
authors.affiliation: INRA, UMR1349, Institute of Genetics, Environment and Plant Protection, Domaine de la Motte, Le Rheu, France; INRIA Centre Rennes - Bretagne Atlantique, GenOuest, Campus de Beaulieu, Rennes, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Legeai
authors.affiliation: INRA, UMR1349, Institute of Genetics, Environment and Plant Protection, Domaine de la Motte, Le Rheu, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Gauthier
authors.affiliation: INRA, UMR1349, Institute of Genetics, Environment and Plant Protection, Domaine de la Motte, Le Rheu, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Prunier-Leterme
authors.affiliation: INRA, UMR1349, Institute of Genetics, Environment and Plant Protection, Domaine de la Motte, Le Rheu, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Tagu
authors.affiliation: INRA, UMR1349, Institute of Genetics, Environment and Plant Protection, Domaine de la Motte, Le Rheu, France.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Simon
mesh_terms: D000818:Animals; D001042:Aphids / Q000235:genetics* / Q000502:physiology; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D005260:Female; D022761:Gene Transfer, Horizontal; D005828:Genetics, Population; D008297:Male; D010312:Parthenogenesis / Q000235:genetics; D018532:Pisum sativum / Q000469:parasitology*; D040641:Quantitative Trait Loci; D012098:Reproduction / Q000235:genetics; D012100:Reproduction, Asexual / Q000235:genetics*