Effects of different f2 schemes on qtl mapping in pigs | 猪F2代资源家系的群体结构对QTL定位的影响

Chinese. 【目的】研究猪F2代资源家系的群体结构对数量性状座位(quantitative trait loci,QTL)定位的影响,为QTL定位群体的构建提供参考。【方法】通过模拟的方法,模拟了18种不同的群体结构,研究F0代(亲本)、F1代和F2代群体大小、F0代和F1代公母比例以及祖代QTL基因频率等6种因素对QTL定位的影响。【结果】随着F2代群体的增大,QTL检测的效率明显提高,加性效应的估计值逐渐偏低,95%置信区间显著减小。造成加性效应降低的主要原因是QTL在两亲本群体中没有纯合。随着F0代母畜比例的增加,QTL 95%置信区间也明显降低;随着祖代QTL基因频率差异的增加,QTL检测的效率和准确性都显著提高。【结论】F2代群体大小、F0代母猪比例和祖代QTL基因频率对QTL定位有显著影响,而F1代的群体大小、F0代的群体大小和F1代公母比例对QTL定位的影响不显著。

English. 【Objective】To optimize the QTL mapping design in pigs, the effects of different F2 schemes on QTL mapping were investigated using a simulation method. 【Method】 Using a simulation method, 18 population structures were simulated to evaluate the effects of the numbers of individuals in F0, F1 and F2 generations, the ratios of males to females in F1 and F2 generations and the QTL frequencies in Fo generation on QTL mapping. 【Result】With the increasing number of F2 individuals, the power of QTL detection increased, and the 95% confidence interval narrowed, while the estimate of the addictive effect of the QTL was downward. The reason for the downward biased estimator of addictive effect was that the QTL alleles were not alternatively fixed in the two founder breeds. As the proportion of F0 females increasing, the 95% confidence interval reduced. The power and the estimates were improved with the difference of QTL frequencies increasing in the founder populations. 【Conclusion】The number of F2 animals, the proportion of F0 females and the QTL allele frequencies in Fo generation had significant effects on QTL detection, but the numbers of F1 and F0 individuals and the proportion of F1 females had no significant effect on the QTL mapping.