Jongjoo Kim, Davis Scott K, Taylor Jeremy F
Animal Science Department, Texas A&M University, College Station 78743, USA.
Genet Res. 2002 Jun;79(3):259-63. doi: 10.1017/s001667230200561x.
Empirical confidence intervals (CIs) for the estimated quantitative trait locus (QTL) location from selective and non-selective non-parametric bootstrap resampling methods were compared for a genome scan involving an Angus x Brahman reciprocal fullsib backcross population. Genetic maps, based on 357 microsatellite markers, were constructed for 29 chromosomes using CRI-MAP V2.4. Twelve growth, carcass composition and beef quality traits (n = 527-602) were analysed to detect QTLs utilizing (composite) interval mapping approaches. CIs were investigated for 28 likelihood ratio test statistic (LRT) profiles for the one QTL per chromosome model. The CIs from the non-selective bootstrap method were largest (87 7 cM average or 79-2% coverage of test chromosomes). The Selective II procedure produced the smallest CI size (42.3 cM average). However, CI sizes from the Selective II procedure were more variable than those produced by the two LOD drop method. CI ranges from the Selective II procedure were also asymmetrical (relative to the most likely QTL position) due to the bias caused by the tendency for the estimated QTL position to be at a marker position in the bootstrap samples and due to monotonicity and asymmetry of the LRT curve in the original sample.
在一项涉及安格斯牛与婆罗门牛相互全同胞回交群体的基因组扫描中，比较了通过选择性和非选择性非参数自助重采样方法估计数量性状基因座（QTL）位置的经验置信区间（CI）。使用CRI-MAP V2.4软件，基于357个微卫星标记构建了29条染色体的遗传图谱。利用（复合）区间作图方法分析了12个生长、胴体组成和牛肉品质性状（n = 527 - 602）以检测QTL。针对每条染色体一个QTL模型的28个似然比检验统计量（LRT）分布图研究了置信区间。非选择性自助法得到的置信区间最大（平均87.7 cM，占测试染色体的79.2%）。选择性II程序产生的置信区间大小最小（平均42.3 cM）。然而，选择性II程序得到的置信区间大小比双LOD下降法产生的更具变异性。由于自助样本中估计的QTL位置倾向于处于标记位置所导致的偏差，以及原始样本中LRT曲线的单调性和不对称性，选择性II程序的置信区间范围（相对于最可能的QTL位置）也是不对称的。
