Gardner Kyle M, Latta Robert G
Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, Nova Scotia, Canada B3H 4J1.
Mol Ecol. 2007 Oct;16(20):4195-209. doi: 10.1111/j.1365-294X.2007.03499.x. Epub 2007 Sep 10.
We review genetic correlations among quantitative traits in light of their underlying quantitative trait loci (QTL). We derive an expectation of genetic correlation from the effects of underlying loci and test whether published genetic correlations can be explained by the QTL underlying the traits. While genetically correlated traits shared more QTL (33%) on average than uncorrelated traits (11%), the actual number of shared QTL shared was small. QTL usually predicted the sign of the correlation with good accuracy, but the quantitative prediction was poor. Approximately 25% of trait pairs in the data set had at least one QTL with antagonistic effects. Yet a significant minority (20%) of such trait pairs have net positive genetic correlations due to such antagonistic QTL 'hidden' within positive genetic correlations. We review the evidence on whether shared QTL represent single pleiotropic loci or closely linked monotropic genes, and argue that strict pleiotropy can be viewed as one end of a continuum of recombination rates where r=0. QTL studies of genetic correlation will likely be insufficient to predict evolutionary trajectories over long time spans in large panmictic populations, but will provide important insights into the trade-offs involved in population and species divergence.
我们根据潜在的数量性状基因座（QTL）来审视数量性状之间的遗传相关性。我们从潜在基因座的效应中推导出遗传相关性的预期值，并检验已发表的遗传相关性是否可以由性状背后的QTL来解释。虽然遗传相关的性状平均比不相关的性状共享更多的QTL（33%），而不相关的性状平均共享11%，但实际共享的QTL数量很少。QTL通常能很好地预测相关性的方向，但定量预测效果不佳。数据集中约25%的性状对至少有一个具有拮抗作用的QTL。然而，由于这种拮抗QTL“隐藏”在正遗传相关性中，相当少数（20%）的此类性状对具有净正遗传相关性。我们审视了关于共享QTL代表单个多效性基因座还是紧密连锁的单效性基因的证据，并认为严格的多效性可被视为重组率连续体的一端，其中r = 0。对遗传相关性的QTL研究可能不足以预测大随机交配种群在长时间跨度内的进化轨迹，但将为种群和物种分化所涉及的权衡提供重要见解。
