数量性状基因图谱构建方法的比较

Comparison among Mapping Methods for Detecting QTLs and Estimating Their Effects

应用方差分析法(ANOVA)、区间作图法(IM)和复合区间作图法(CIM),分析玉米组合Ki3×CML139的F_2群体有关玉米螟抗性、株高和穗位高的数量性状基因(QTL)图谱。结果表明:(1)在同一显著水平下(。=0.0032),ANOVA共发现25个QTL,而IM为21个,CIM为23个。说明ANOVA虽然难以精确标定QTL的位置,但其发现能力仍可能是最高的。(2)在总共发现的30个QTL中,3种方法都发现的有15个,两种方法共同发现的有9个,仅由一种方法发现的有6个,说明3种方法的同一性仍是主要的。值得注意的是CIM法单独发现的QTL达4个之多,但其可重复性尚待验证。(3)3种方法估计的QTL的平均加性效应(?)和显性效应(?)均无显著差异,而且方法间变异大多小于方法内变异。(4)建议以几种方法构建QTL图谱,并优先标定共同发现的QTL;QTL的效应可以合并估计。

Three typical mapping methods, the analysis of variance (ANOVA), the interval mapping(IM) and the composite interval mapping (CIM), were employed to construct the QTL maps of corn borer resistance, plant height and ear height for an F2 data of the cross Ki3× CML139 from CIMMYT. Numbers, positions and effects of detected QTLs by these methods were compared. The results are as follows. (1) 25 significant QTLs were detected by ANOVA, 21 QTLs by IM, and 23 QTLs by CIM for the three traits under the same significant level. So ANOVA had the highest capability for the detection although it might bias the estimates for positions and effects. (2) The same 15 QTLs of all 30 were detected by the three methods, other 9 QTLs were found out by two of the three methods, another 6 QTLs by only one method. This indicated that the similarity among methods was dominant. (3) The differences among whether average additive effects (absolute values) or dominant effects (practical values) of QTLs estimated by different methods were insignificant, and the variation among methods was smaller than that within methods in general. (4) A suggestion for mapping QTLs is that multiple methods should be considered, and it is preferential to declare the QTLs detected simultaneously by several methods, and then jointly estimate their effects.