Genome-wide mapping of QTL associated with heterosis in the RIL-based NCIII design
Genome-wide mapping of QTL associated with heterosis in the RIL-based NCIII design
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基于 RIL 的 NCIII 设计中与杂种优势相关的 QTL 的全基因组定位
DOI：
10.1007/s11434-012-5127-x
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发表时间：
2012-07-01
影响因子：
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通讯作者：
Zhang Yuan-Ming
中科院分区：
文献类型：
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作者：
He XiaoHong;Hu ZhongLi;Zhang Yuan-Ming
杂种优势是作物改良中最具革命性的进步之一。在杂种优势的遗传剖析中，NCIII设计是一种最有力、应用最广泛的配种方案。然而，目前设计中的QTL检测方法多基于复合区间映射。因此，在本研究中，我们的目的是开发一种统计方法来定位基于ril的NCIII设计中与杂种优势相关的上位QTL。首先，我们推导了两个经典线性变换z1和z2的期望，在F∞和f2度量模型下，一个数量性状由两个具有遗传上位性和任意连锁的QTL控制。然后，我们构建了包含全基因组上所有标记的上位遗传模型，并利用经验贝叶斯方法估计了模型中的所有参数。最后，进行了一系列蒙特卡罗仿真实验来验证所提出的方法。结果表明：(1)主效QTL的扩增遗传参数均能正确识别，统计能力和精度均较好；(2)单纯上位效应的符号对增强型上位效应检测的统计能力有实质性影响；(3)上位性QTL的检测难度大于主效QTL的检测难度；(4)基于ril的NCIII设计的统计能力高于基于f2的NCIII设计，特别是在检测由两个相反方向的纯上位效应组成的增强型上位效应方面。
Heterosis represents one of the most revolutionary advancements in crop improvement. In the genetic dissection of heterosis, NCIII design is one of the most powerful and widely used mating schemes. However, the methodologies for quantitative trait loci (QTL) detection in the design were mostly based on composite interval mapping. Therefore, in this study, our purpose was to develop a statistical method for mapping epistatic QTL associated with heterosis in the RIL-based NCIII design. First, we derivated the expectations of two classical linear transformations,Z1andZ2, while a quantitative trait was controlled by two QTL with digenic epistasis and arbitrary linkage under the F∞and F2metric models. Then, we constructed an epistatic genetic model that includes all markers on the whole genome simultaneously, and estimated all the parameters in the model by the empirical Bayes approach. Finally, a series of Monte Carlo simulation experiments was carried out to confirm the proposed approach. The results show that: (1) all the augmented genetic parameters for main-effect QTL could be rightly identified with satisfactory statistical power and precision; (2) the statistical powers in the detection of augmented epistatic effects were substantively affected by the signs of pure epistatic effects; (3) it is more difficult to detect epistatic QTL than to detect main-effect QTL; (4) statistical power is higher in the RIL-based NCIII design than in the F2-based NCIII design, especially in the detection of the augmented epistatic effect that consists of two pure epistatic effects in opposite directions.