{新}QTL定位中常见的12个问题.doc

数量性状基因定位研究中若干常见问题的 李慧慧 张鲁燕 王建康* 中国农业科学院作物科学研究所/国家农作物基因资源与基因改良重大科学工程/CIMMYT中国办事处，北京100081 摘 要：QTL作图是基因精细定位、克隆以及有效开展分子育种的基础，在利用QTL作图开展数量性状基因定位研究的过程中经常碰到一些问题，与统计方法有关的一些问题包括：LOD的统计学意义是什么？检测QTL的可信度和LOD临界值的关系是什么？如何评价不同的QTL作图方法？提高QTL检测效率的途径有哪些？与遗传参数估计有关的一些问题包括：QTL的贡献率是如何计算出来的？如何确定QTL有利等位基因的来源？选择基因型分析的有效性如何？复合性状是否适宜于QTL作图？与作图群体及遗传图谱有关的一些问题包括：QTL作图群体中表型数据是否要求服从正态分布？加密标记是否可以显著提高QTL检测功效？缺失分子标记对QTL作图有什么影响？奇异分离标记对QTL作图有什么影响？笔者试图结合我们多年的研究工作对这些具有共性的12个常见问题做出解答，供科研工作者参考。 关键词：数量性状；QTL作图；完备区间作图；似然比检验；功效分析 Analytical Answers to Frequently Asked Questions in Quantitative Trait Locus Mapping LI Hui-Hui, ZHANG Lu-Yan, and WANG Jian-Kang* Institute of Crop Sciences / National Key Facility for Crop Gene Resources and Genetic Improvement / CIMMYT China Office, Chinese Academy of Agricultural Sciences, Beijing 100081, China( Abstract: QTL mapping is an important step in gene fine mapping, map-based cloning, and the efficient use of gene information in molecular breeding. Questions are frequently met and asked in the application of QTL mapping in practical genetic populations. Questions related to statistical method of QTL mapping are: what does LOD score mean? What is the relationship between the reliability of detected QTL and the LOD threshold? How to evaluate different QTL mapping methods? How to improve the QTL detection power? Questions related to genetic parameter estimation are: how to calculate the phenotypic variance explained by each detected QTL? How to determine the source of favorable alleles at detected QTL? How efficient is the selective genotyping? Can composite traits be used in QTL mapping? Questions related to linkage map and mapping populations are: Does the phenotype of a trait of interest have to follow a normal distribution? Does the increase in marker density greatly improve QTL mapping power? What effects will missing markers have in QTL mapping? What effects will segregation distortion have in QTL mapping? Our objective in this paper is to provide the analytical