Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, 100083, China.
Center for Computational Biology, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.
Plant J. 2019 Mar;97(6):1168-1182. doi: 10.1111/tpj.14185. Epub 2019 Feb 12.
Many quantitative traits are composites of other traits that contribute differentially to genetic variation. Quantitative trait locus (QTL) mapping of these composite traits can benefit by incorporating the mechanistic process of how their formation is mediated by the underlying components. We propose a dissection model by which to map these interconnected components traits under a joint likelihood setting. The model can test how a composite trait is determined by pleiotropic QTLs for its component traits or jointly by different sets of QTLs each responsible for a different component. The model can visualize the pattern of time-varying genetic effects for individual components and their impacts on composite traits. The dissection model was used to map two composite traits, stemwood volume growth decomposed into its stem height, stem diameter and stem form components for Euramerican poplar adult trees, and total lateral root length constituted by its average lateral root length and lateral root number components for Euphrates poplar seedlings. We found the pattern of how QTLs for different components contribute to phenotypic variation in composite traits. The detailed understanding of the genetic machineries of composite traits will not only help in the design of molecular breeding in plants and animals, but also shed light on the evolutionary processes of quantitative traits under natural selection.
许多数量性状是由对遗传变异有不同贡献的其他性状组成的。这些复合性状的数量性状基因座（QTL）图谱可以通过纳入其形成机制来受益，这些机制是由潜在成分介导的。我们提出了一种剖分模型，以便在联合似然设置下对这些相互关联的成分性状进行映射。该模型可以测试复合性状是如何由其组成性状的多效性 QTL 决定的，或者是由不同的 QTL 集合共同决定的，每个 QTL 负责不同的组成部分。该模型可以直观地显示个体成分的时变遗传效应及其对复合性状的影响。剖分模型用于映射两个复合性状，即欧美杨成树的木材体积生长分解为其茎高、茎直径和茎形组成部分，以及幼龄杨树的总侧根长度由其平均侧根长度和侧根数量组成部分。我们发现了不同成分的 QTL 如何对复合性状的表型变异做出贡献的模式。对复合性状遗传机制的详细了解不仅有助于动植物的分子育种设计，也有助于阐明自然选择下数量性状的进化过程。
