Erickson David L, Fenster Charles B, Stenøien Hans K, Price Donald
Laboratory of Analytical Biology, Smithsonian Institution, Suitland, MD 20746, USA.
Mol Ecol. 2004 Sep;13(9):2505-22. doi: 10.1111/j.1365-294X.2004.02254.x.
The past decade has seen a proliferation of studies that employ quantitative trait locus (QTL) approaches to diagnose the genetic basis of trait evolution. Advances in molecular techniques and analytical methods have suggested that an exact genetic description of the number and distribution of genes affecting a trait can be obtained. Although this possibility has met with some success in model systems such as Drosophila and Arabidopsis, the pursuit of an exact description of QTL effects, i.e. individual gene effect, in most cases has proven problematic. We discuss why QTL methods will have difficulty in identifying individual genes contributing to trait variation, and distinguish between the identification of QTL (or marker intervals) and the identification of individual genes or nucleotide differences within genes (QTN). This review focuses on what ecologists and evolutionary biologists working with natural populations can realistically expect to learn from QTL studies. We highlight representative issues in ecology and evolutionary biology and discuss the range of questions that can be addressed satisfactorily using QTL approaches. We specifically address developing approaches to QTL analysis in outbred populations, and discuss practical considerations of experimental (cross) design and application of different marker types. Throughout this review we attempt to provide a balanced description of the benefits of QTL methodology to studies in ecology and evolution as well as the inherent assumptions and limitations that may constrain its application.
在过去十年中，采用数量性状基因座（QTL）方法来诊断性状进化遗传基础的研究大量涌现。分子技术和分析方法的进步表明，可以获得影响某一性状的基因数量和分布的精确遗传描述。尽管这种可能性在果蝇和拟南芥等模式系统中取得了一些成功，但在大多数情况下，追求对QTL效应（即单个基因效应）的精确描述已被证明存在问题。我们讨论了为什么QTL方法在识别导致性状变异的单个基因方面会遇到困难，并区分了QTL（或标记区间）的识别与基因内单个基因或核苷酸差异（QTN）的识别。本综述重点关注研究自然种群的生态学家和进化生物学家实际能从QTL研究中学到什么。我们突出了生态与进化生物学中的代表性问题，并讨论了使用QTL方法能够令人满意地解决的一系列问题。我们特别探讨了远交群体中QTL分析的发展方法，并讨论了实验（杂交）设计和不同标记类型应用的实际考量。在本综述中，我们试图对QTL方法对生态与进化研究的益处以及可能限制其应用的固有假设和局限性进行全面描述。
