利用改进的复合区间作图法和F1代群体进行杉木的QTL作图

QTL Mapping in Chinese Fir Using Modified Composite Interval Mapping Method and F_1 Population

区间作图和复合区间作图最先是为近交群体而设计的QTL作图方法 ,现已得到了广泛的应用。本文将它们应用于林木的F1代群体的QTL作图 ,称为改进的区间作图和复合区间作图法。该方法考虑了林木F1代 1∶1分离位点的信息 ,不同于通常的“拟测交”作图法。采用该方法 ,本文利用两个杉木无性系句容 0号杉和柔叶杉的AFLP分子标记遗传连锁图谱对杉木的 13个数量性状进行了QTL定位。当似然比统计量的阀值取为 13 82 (对应于LOD为 3 0 )时 ,在两张杉木遗传连锁图谱上 ,共搜索到了 2 5个QTL。在句容 0号无性系遗传连锁图谱上 ,有 5个QTL分布在 4个连锁群上。在柔叶杉的遗传连锁图谱上 ,有 2 0个QTL分布在 3个连锁群上 ,其中第 6连锁群上集中了高达 13个QTL。这一新的QTL作图方法在作图精度上有了较大的提高。文中所有的计算都是使用Mathematica软件编程完成的。

Interval mapping (IM) and Complex interval mapping (CIM) were designed for mapping QTLs in populations of inbred lines and now have been applied extensively. The IM and CIM methods were applied to the F 1 generations of forest trees in this paper and can be called modified interval mapping and modified complex interval mapping, respectively. Incorporating the 1∶1 segregation loci in F 1 generation of forest trees, the modified IM and CIM were not similar to the ‘pseudo-testcross' method which was usually used in QTL mapping in forest trees. Based on the two genetic linkage maps of Chinese fir clones, ‘Jurong 0' and ‘Rouye', the quantitative traits controlling 13 growth and morphological traits were located by using the modified composite interval mapping method. Twenty five QTLs were detected at the threshold value of maximum likelihood ratio, 13.82(corresponding to LOD=3.0). There were 5 QTLs on the Chinese fir genetic linkage map of ‘Jurong 0' and 20 QTLs on the map of ‘Rouye'. The precision of the new QTL mapping method in F 1 generation of Chinese fir was improved. All the computing in this paper was implemented by programming with Mathemtica software.