title: Transient Microgeographic Clines during B Chromosome Invasion.
abstract: The near-neutral model of B chromosome evolution predicts that the invasion of a new population should last some tens of generations, but the details on how it proceeds in real populations are mostly unknown. Trying to fill this gap, we analyze here a natural population of the grasshopper Eyprepocnemis plorans at three time points during the last 35 years. Our results show that B chromosome frequency increased significantly during this period and that a cline observed in 1992 had disappeared in 2012 once B chromosome frequency reached an upper limit at all sites sampled. This indicates that, during B chromosome invasion, transient clines for B chromosome frequency are formed at the invasion front on a microgeographic scale. Computer simulation experiments showed that the pattern of change observed for genotypic frequencies is consistent with the existence of B chromosome drive through females and selection against individuals with a high number of B chromosomes.
authors.affiliation: Departamento de Genética, Facultad de Ciencias, Avenida Fuentenueva s/n, Universidad de Granada, 18071 Granada, Spain.
authors.forename: Juan Pedro M
authors.initials: JP
authors.lastname: Camacho
authors.forename: Michael W
authors.initials: MW
authors.lastname: Shaw
authors.forename: Josefa
authors.initials: J
authors.lastname: Cabrero
authors.forename: Mohammed
authors.initials: M
authors.lastname: Bakkali
authors.forename: Mercedes
authors.initials: M
authors.lastname: Ruíz-Estévez
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Ruíz-Ruano
authors.forename: Rubén
authors.initials: R
authors.lastname: Martín-Blázquez
authors.forename: María Dolores
authors.initials: MD
authors.lastname: López-León
mesh_terms: D000818:Animals; D059006:Chromosomes, Insect / Q000235:genetics*; D003198:Computer Simulation; D005260:Female; D006110:Grasshoppers / Q000235:genetics*; D008297:Male; D008954:Models, Biological; D012621:Seasons; D013030:Spain