THE INFLUENCE OF MATERNAL EFFECTS ON ACCURACY OF EVALUATION OF LITTER SIZE IN SWINE
THE INFLUENCE OF MATERNAL EFFECTS ON ACCURACY OF EVALUATION OF LITTER SIZE IN SWINE
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DOI：
10.2527/1993.7192353x
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发表时间：
1993-09-01
影响因子：
3.3
通讯作者：
KENNEDY, BW
中科院分区：
文献类型：
--
作者：
ROEHE, R;KENNEDY, BW
通过随机模拟研究了母体遗传效应对选择反应的影响。一个封闭的120头母猪，每年有24头公猪进入育种群的选择过程，模拟了10年。不同程度的母体遗传力的影响（0，.025，.05），母体效应和直接效应之间的遗传相关（0，-.5，-.9）和评价模型（有或没有母体效应，称为完全或不完全模型）对选择的反应，评估的准确性，预测误差方差（PEV），偏倚，和均方误差（MSE）进行了分析的窝产仔数的直接遗传力为0.10。在动物模型下，替代动物的定向选择是对第一胎产仔数的直接影响的EBV。使用一个完整的动物模型与母亲的影响，直接遗传效应的反应增加与幅度的母亲遗传力（0至.05）从2.22至2.32头猪10年后，当有没有直接和母亲的影响之间的相关性。此外，获得了阳性母体反应（母体遗传性> 0），尽管没有对母体EBV进行选择。减少直接反应，由于直接和母亲的影响之间的负遗传相关性高达18%，经过10年的选择。更重要的是阴性母体反应，10年后高达-1.27头猪，遗传相关为-0.9。因此，整体遗传优点（孕产妇加直接）减少了77%相比，孕产妇和直接影响是遗传独立的。女性育种值的估计高达36%，比男性更准确。遗传和环境趋势的估计，当母亲的影响被忽略在评估模型（不完全模型），是有偏差的。建议在第一胎产仔数评价模型中考虑母体效应。
The influence of maternal genetic effects on response to selection was examined by stochastic simulation. The selection process of a closed herd of 120 sows, with 24 boars entering the breeding herd each year, was simulated over 10 yr. Effects of different magnitudes of maternal heritability (0, .025, .05), genetic correlations between maternal and direct effects (0, -.5, -.9) and evaluation models (with or without maternal effects, referred to as complete or incomplete model) on response to selection, accuracy of evaluation, prediction error variance (PEV), bias, and mean squared error (MSE) were analyzed for litter size with a direct heritability of .10. Directional selection of replacement animals was on EBV of direct effects for first-parity litter size under an animal model. Using a complete animal model with maternal effects, response in direct genetic effects increased with magnitude of maternal heritability (0 to .05) from 2.22 to 2.32 pigs after 10 yr, when there was no correlation between direct and maternal effects. Additionally, a positive maternal response was achieved (with maternal heritability > 0), although no selection was on maternal EBV. Reduction in direct response due to negative genetic correlations between direct and maternal effects was up to 18% after 10 yr of selection. More important was the negative maternal response, which was up to -1.27 pigs after 10 yr for a genetic correlation of -.9. Consequently, the overall genetic merit (maternal plus direct) was reduced up to 77% compared with when maternal and direct effects were genetically independent. Estimation of female breeding values was up to 36% more accurate than in males. Estimates of genetic and environmental trend, when maternal effects were ignored in the evaluation model (incomplete model), were biased. Consideration of maternal effects in the evaluation model of first-parity litter size was recommended.