Keeping it local: evidence for positive selection in Swedish Arabidopsis thaliana.
Bottom Line: The model plant Arabidopsis thaliana exemplifies this problem: In spite of the large amounts of data, little evidence for classic selective sweeps has been found.Moreover, it affects the power differently for northern Sweden (more false positives) as compared with southern Sweden (more false negatives).This study demonstrates the necessity of combining demographic analyses and sweep scans for the detection of selection, particularly when selection acts predominantly local.
Affiliation: Mathematics and BioSciences Group, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna, Austria.Show MeSH
Mentions: Within the two-deme framework, we modeled a number of potential evolutionary histories. All models begin with the split of the ancestral population and allow for the exchange of migrants. We allow for variable and asymmetric migration, secondary contact after a phase of separation, different deme sizes, population size changes (including bottlenecks) either at the split time or afterwards, and variable split times from the common ancestor. In addition, we model three different admixture scenarios in order to simulate two postglacial waves of expansion (François et al. 2008). In total, we tested 14 models with 4–9 parameters using (Gutenkunst et al. 2009). A summary of the tested models is given in table 1 and figure 2.Fig. 2.
Affiliation: Mathematics and BioSciences Group, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna, Austria.