title: Contemporary gene flow and mating system of Arabis alpina in a Central European alpine landscape.
abstract: OBJECTIVE
  Gene flow is important in counteracting the divergence of populations but also in spreading genes among populations. However, contemporary gene flow is not well understood across alpine landscapes. The aim of this study was to estimate contemporary gene flow through pollen and to examine the realized mating system in the alpine perennial plant, Arabis alpina (Brassicaceae).
  
  
  METHODS
  An entire sub-alpine to alpine landscape of 2 km(2) was exhaustively sampled in the Swiss Alps. Eighteen nuclear microsatellite loci were used to genotype 595 individuals and 499 offspring from 49 maternal plants. Contemporary gene flow by pollen was estimated from paternity analysis, matching the genotypes of maternal plants and offspring to the pool of likely father plants. Realized mating patterns and genetic structure were also estimated.
  
  
  RESULTS
  Paternity analysis revealed several long-distance gene flow events (≤1 km). However, most outcrossing pollen was dispersed close to the mother plants, and 84 % of all offspring were selfed. Individuals that were spatially close were more related than by chance and were also more likely to be connected by pollen dispersal.
  
  
  CONCLUSIONS
  In the alpine landscape studied, genetic structure occurred on small spatial scales as expected for alpine plants. However, gene flow also covered large distances. This makes it plausible for alpine plants to spread beneficial alleles at least via pollen across landscapes at a short time scale. Thus, gene flow potentially facilitates rapid adaptation in A. alpina likely to be required under ongoing climate change.
authors.affiliation: WSL Swiss Federal Research Institute, Zürcherstrasse 111, Birmensdorf, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Buehler
authors.forename: R
authors.initials: R
authors.lastname: Graf
authors.forename: R
authors.initials: R
authors.lastname: Holderegger
authors.forename: F
authors.initials: F
authors.lastname: Gugerli
mesh_terms: D031214:Arabis / Q000235:genetics* / Q000502:physiology; D051456:Gene Flow; D018895:Microsatellite Repeats / Q000235:genetics; D012098:Reproduction