Ansell, Stephen , Grundmann, Michael , Russell, Stephen J. , Schneider, Harald , Vogel, Johannes C. .
Population structure of Arabidopsis lyrata: Implications for model organism research.
Arabidopsis lyrata is closely related to the model plant A. thaliana and has emerged as a model system for plant evolutionary and ecological genetics. Its genome will shortly be sequenced and the optimisation of the resource requires that the confounding effects of demographic history and selection are untangled. Here we present a comprehensive survey of the entire range of the European A. lyrata ssp. petraea, utilising both nuclear (allozyme) and chloroplast (trnL-F IGS) genetic markers, with multiple samples per disjunct area. Within-population diversity was substantial for nuclear markers (mean P=0.620, Ae=1.575, Ho=0.247) and diversity was significant partitioned among populations (FST= 0.249). Both Bayesian and distance analyses of nuclear data identified discrete northern and central European gene pools and a highly congruent geographic pattern was recovered from the distribution of chloroplast haplotypes. While the northern populations display a modest inbreeding increase (FIS=0.088 verses FIS=0. 0.135), there is no evidence of recent bottlenecks, and values of P, Ae and Ho did not differ significantly to central European populations. With no extant populations recorded in the traditional southern refugia, we speculate that A. l. petraea preference for disturbed humid rocky habitats and cold-tolerance enabled it to survive the Quarternary glaciations between the alpine and Nordic glaciers in two independent refugia: one in central Europe and one cryptic refugium. The subsequent post-glacial expansion in northern European probably occurred at the margin of the receding ice-sheets thus preserving diversity. Despite recent divergence and seemingly different ecological preferences, the population history and diversity patterns of the two Arabidopsis model systems are distinct. Wider implications for model organism research and sampling strategies are discussed.
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1 - Natural History Museum, Department of Botany, Cromwell Road, London, SW7 5BD, England
2 - Natural History Museum, Cromwell Road, London, SW7 5BD, UK
Presentation Type: Oral Paper:Papers for Topics
Date: Tuesday, July 29th, 2008
Time: 10:15 AM