Nejati-Javaremi A, Smith C, Gibson J P
Department of Animal and Poultry Science, University of Guelph, Ontario, Canada.
J Anim Sci. 1997 Jul;75(7):1738-45. doi: 10.2527/1997.7571738x.
Total allelic relationship (TA) as a possible alternative to the pedigree-derived additive genetic relationship (RA) is defined. The TA measures the actual allelic identity between individuals for loci segregating for the trait concerned. Its value was studied by simulation in populations of different family structure, different numbers of loci, different numbers of alleles per locus, and different heritability levels. The alternative types of relationship matrices were used in mixed model equations to derive best linear unbiased prediction estimates (EBV) of breeding values (BV). Accuracies of evaluations were calculated as correlations of EBV with true breeding values. In populations with random selection and mating, EBVTA derived using TA had higher accuracies than EBVRA derived using RA. In populations with selection, EBVTA was more accurate and resulted in higher responses than selection on EBVRA. We conclude that not accounting for variation in average measures of relationship and identity in state can be important sources of variance of prediction error, and taking account of them increases the accuracy of selection.
定义了总等位基因关系（TA），作为系谱衍生的加性遗传关系（RA）的一种可能替代方法。TA衡量了在与所关注性状分离的位点上个体之间实际的等位基因一致性。通过在不同家庭结构、不同位点数量、每个位点不同等位基因数量以及不同遗传力水平的群体中进行模拟研究了其值。在混合模型方程中使用了替代类型的关系矩阵，以得出育种值（BV）的最佳线性无偏预测估计值（EBV）。评估的准确性通过EBV与真实育种值的相关性来计算。在随机选择和交配的群体中，使用TA得出的EBVTA比使用RA得出的EBVRA具有更高的准确性。在有选择的群体中，EBVTA更准确，并且比基于EBVRA的选择产生更高的响应。我们得出结论，不考虑关系和状态一致性平均度量的变化可能是预测误差方差的重要来源，考虑这些因素会提高选择的准确性。
