Department of Animal Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
Department of Biological Sciences, Institute for Bioinformatics and Evolutionary Studies, University of Idaho, 875 Perimeter Drive, Moscow, ID, 83844, USA.
Mol Ecol Resour. 2017 May;17(3):362-365. doi: 10.1111/1755-0998.12669. Epub 2017 Apr 11.
Recently, Lowry et al. addressed the ability of RADseq approaches to detect loci under selection in genome scans. While the authors raise important considerations, such as accounting for the extent of linkage disequilibrium in a study system, we strongly disagree with their overall view of the ability of RADseq to inform our understanding of the genetic basis of adaptation. The family of RADseq protocols has radically improved the field of population genomics, expanding by several orders of magnitude the number of markers available while substantially reducing the cost per marker. Researchers whose goal is to identify regions of the genome under selection must consider the LD of the experimental system; however, there is no magical LD cutoff below which researchers should refuse to use RADseq. Lowry et al. further made two major arguments: a theoretical argument that modeled the likelihood of detecting selective sweeps with RAD markers, and gross summaries based on an anecdotal collection of RAD studies. Unfortunately, their simulations were off by two orders of magnitude in the worst case, while their anecdotes merely showed that it is possible to get widely divergent densities of RAD tags for any particular experiment, either by design or due to experimental efficacy. We strongly argue that RADseq remains a powerful and efficient approach that provides sufficient marker density for studying selection in many natural populations. Given limited resources, we argue that researchers should consider a wide range of trade-offs among genomic techniques, in light of their study question and the power of different techniques to answer it.
最近,Lowry 等人研究了 RADseq 方法在基因组扫描中检测选择位点的能力。虽然作者提出了一些重要的考虑因素,例如在研究系统中考虑连锁不平衡的程度,但我们强烈不同意他们对 RADseq 能够为我们理解适应的遗传基础提供信息的总体看法。RADseq 协议家族极大地改进了群体基因组学领域,将可用标记的数量增加了几个数量级,同时大大降低了每个标记的成本。那些旨在识别基因组中受选择区域的研究人员必须考虑实验系统的 LD;然而,并没有一个神奇的 LD 截止值,低于这个值,研究人员就应该拒绝使用 RADseq。Lowry 等人进一步提出了两个主要论点:一个是基于 RAD 标记检测选择扫掠的可能性的理论论证,另一个是基于 RAD 研究的轶事收集的总括。不幸的是,他们的模拟在最坏的情况下相差两个数量级,而他们的轶事仅仅表明,对于任何特定的实验,无论是通过设计还是由于实验效果,都有可能获得广泛不同的 RAD 标记密度。我们强烈认为,RADseq 仍然是一种强大而有效的方法,它为研究许多自然种群中的选择提供了足够的标记密度。鉴于资源有限,我们认为研究人员应该根据他们的研究问题和不同技术回答问题的能力,考虑基因组技术之间的广泛权衡。