School of Aquatic and Fishery Sciences, University of Washington, 1122 NE Boat Street, Box 355020, Seattle, WA, 98195-5020, USA.
U.S. Geological Survey, Wisconsin Cooperative Fishery Research Unit, College of Natural Resources, University of Wisconsin-Stevens Point, 800 Reserve St., Stevens Point, WI, 54481, USA.
Mol Ecol Resour. 2017 May;17(3):356-361. doi: 10.1111/1755-0998.12649. Epub 2017 Feb 9.
In their recently corrected manuscript, "Breaking RAD: An evaluation of the utility of restriction site associated DNA sequencing for genome scans of adaptation", Lowry et al. argue that genome scans using RADseq will miss many loci under selection due to a combination of sparse marker density and low levels of linkage disequilibrium in most species. We agree that marker density and levels of LD are important considerations when designing a RADseq study; however, we dispute that RAD-based genome scans are as prone to failure as Lowry et al. suggest. Their arguments ignore the flexible nature of RADseq; the availability of different restriction enzymes and capacity for combining restriction enzymes ensures that a well-designed study should be able to generate enough markers for efficient genome coverage. We further believe that simplifying assumptions about linkage disequilibrium in their simulations are invalid in many species. Finally, it is important to note that the alternative methods proposed by Lowry et al. have limitations equal to or greater than RADseq. The wealth of studies with positive impactful findings that have used RAD genome scans instead supports the argument that properly conducted RAD genome scans are an effective method for gaining insight into ecology and evolution, particularly for non-model organisms and those with large or complex genomes.
在他们最近修正的手稿《打破 RAD:对限制相关 DNA 测序在适应性基因组扫描中效用的评估》中,Lowry 等人认为,由于大多数物种中标记密度稀疏和连锁不平衡水平低的综合作用,使用 RADseq 的基因组扫描将错过许多受选择影响的基因座。我们同意在设计 RADseq 研究时,标记密度和 LD 水平是重要的考虑因素;然而,我们不同意 Lowry 等人提出的 RAD 基的基因组扫描容易失败的观点。他们的论点忽略了 RADseq 的灵活性;不同的限制酶的可用性和结合限制酶的能力确保了精心设计的研究应该能够生成足够的标记,以实现有效的基因组覆盖。我们进一步认为,在他们的模拟中简化连锁不平衡的假设在许多物种中是无效的。最后,值得注意的是,Lowry 等人提出的替代方法也存在与 RADseq 相等或更大的局限性。大量具有积极影响的研究使用 RAD 基因组扫描来支持这样的论点,即正确进行的 RAD 基因组扫描是一种有效的方法,可以深入了解生态学和进化,特别是对于非模式生物和那些具有大或复杂基因组的生物。