闭锁群体BLUP选择下遗传方差和近交系数的变化

采用计算机随机模拟方法模拟了在一个闭锁群体内连续对单个性状进行 1 5个世代选择的情况。选择过程中世代不重叠 ,每个世代的种畜根据动物模型最佳线性无偏预测 (BLUP)法估计的育种值进行选留 ,并在此基础上系统地比较了不同群体规模、公母比例和性状遗传力对群体遗传方差和近交系数变化的影响。结果表明 ,扩大育种群规模、增加公畜比例以及对低遗传力性状进行选择时 ,群体遗传方差降低的速度和近交系数上升的速度会更慢 ,在长期选择时可望获得更大的持续进展和适宜的近交增量

Change of genetic variance and inbreeding coefficient in a closed population under BLUP selection

A fifteen-generation continuous selection on a single trait in a closed population was carried out by computer stochastic simulation. There were no overlap generations during the selection. Individual breeding values were estimated through the animal model of best linear unbiased prediction(BLUP), and breeding animals were selected according to their estimated breeding values. The effects of different levels of population size, sire-dam ratio and trait heritability on the change of genetic variance and inbreeding coefficient were studied. The results showed that the speed of genetic variance decreasing and inbreeding coefficient increasing would be slower when the population size and sire ratio was increased and the heritability was lower. In this case, it was expected to gain higher sustainable genetic progress and acceptable inbreeding rate in long-term selection.