Departamento de Bioquímica, Genética e Inmunología, Facultad de Biología, Universidad de Vigo, Vigo, Spain.
J Evol Biol. 2012 Jul;25(7):1364-76. doi: 10.1111/j.1420-9101.2012.02526.x. Epub 2012 May 3.
We investigated the performance of two of the most popular differentiation-based methods to detect loci under selection (dfdist/fdist and bayescan) in order to ascertain the average chromosome map distance between the detected outlier markers and the nearest loci under selection. We used a model of neutral markers genetically linked to selected loci (QTL) controlling a quantitative trait subject to divergent selection in two subpopulations connected by migration. The results are not particularly encouraging because for chromosome lengths above 0.5 morgan, at least 30% of outliers detected were positioned in chromosomes where QTL were absent, clearly denoting false positives. Outliers linked to QTL were on average closer to the nearest QTL than randomly chosen markers, but the methods showed a substantial uncertainty about the genetic association between markers and selected loci, as this association could be shown significantly only in a moderate number of replicates for most scenarios. At equal conditions, bayescan seemed to perform somewhat more efficiently than dfdist/fdist, with little difference between results for dominant and codominant markers.
我们研究了两种最流行的基于分化的方法（dfdist/fdist 和 bayescan）来检测选择下的位点，以确定检测到的异常标记与最近的选择位点之间的平均染色体图谱距离。我们使用了一种模型，其中中性标记与选择位点（QTL）遗传连锁，这些选择位点控制着两个通过迁移连接的亚种群中受分歧选择影响的数量性状。结果并不特别令人鼓舞，因为在染色体长度超过 0.5 摩根的情况下，至少有 30%的异常值被定位在没有 QTL 的染色体上，这显然表示存在假阳性。与 QTL 连锁的异常值比随机选择的标记更接近最近的 QTL，但这些方法对标记与选择位点之间的遗传关联存在很大的不确定性，因为在大多数情况下，只有在中等数量的重复中才能显著显示这种关联。在相同条件下，bayescan 似乎比 dfdist/fdist 效率更高，显性和共显性标记的结果差异不大。
