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: Furthermore, we simulated a scenario of global selection with different average selection strength and local selection. As before, we assume that the same allele is under selection with s = 0.01 in the North, but weaker selection in the South with s = 0.0025. We have chosen a selection coefficient in the South to match the observed CLR values of sweep regions in southern Sweden (table 4). The power of detecting a global, but weaker sweep in southern Sweden is still at 60–70%. Hence, it seems highly unlikely that the five northern sweeps are global, because we should have also seen some of them in the South (fig. 6a).Fig. 6.
Affiliation: Mathematics and BioSciences Group, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria Vienna Graduate School of Population Genetics, Vetmeduni Vienna, Vienna, Austria.