不同QTL增效基因初始频率下标记辅助选择的效果

采用随机模拟方法模拟了在一个闭锁群体内连续对单个性状选择10个世代的情形。在假定选择性状受一个位于常染色体上的QTL和多基因共同控制的情况下，采用动物模型标记辅助最佳线性无偏预测方法估计个体育种值并据此进行种畜的选留，并在此基础上系统地比较了QTL增效基因初始频率对标记辅助选择效果的影响。结果表明：当群体中QTL增效基因的初始频率较低时，选择所获得的QTL基因型值的进展会更大，标记辅助选择在单位时间内可获得较大的遗传进展；此时，尽管QTL增效基因在群体中固定所需的世代数会更长一些，但其频率上升的速度却更快。而QTL增效基因初始频率的高低对群体近交增量的影响不是很大。

Effects of Marker-assisted Selection under Different Initial Frequency of QTL Favorable Allele

A ten-generation continuous selection experiment on a single trait in a closed population was carried out by stochastic simulation.It assumed that the trait was controlled by polygenes and a single autosomal bi-allelic marked quantitative trait locus (QTL).Individual breeding values were estimated through animal model marker-assisted best linear unbiased prediction (MBLUP),and breeding animals were selected according to their breeding values.The effects of three levels initial frequencies of QTL favorable allele on marker-assisted selection (MAS) were studied.The results showed that it would gain higher genetic response when implementing MAS on those traits with lower initial frequency of QTL favorable allele.When the initial frequency of QTL favorable allele was low,although the generation number required for fixing QTL favorable allele in the population would be lengthened,its frequency would be increased faster.However,the initial frequency of QTL favorable allele had little effects on the inbreeding rates.