Breeding programs are judged by the genetic level of animals that are used to disseminate genetic progress. These animals are typically the best ones of the population. To maximise the genetic level of very good animals in the next generation, parents that are more likely to produce top performing offspring need to be selected. The ability of individuals to produce high-performing progeny differs because of differences in their breeding values and gametic variances. Differences in gametic variances among individuals are caused by differences in heterozygosity and linkage. The use of the gametic Mendelian sampling variance has been proposed before, for use in the usefulness criterion or Index5, and in this work, we extend existing approaches by not only considering the gametic Mendelian sampling variance of individuals, but also of their potential offspring. Thus, the criteria developed in this study plan one additional generation ahead. For simplicity, we assumed that the true quantitative trait loci (QTL) effects, genetic map and the haplotypes of all animals are known. In this study, we propose a new selection criterion, ExpBVSelGrOff, which describes the genetic level of selected grand-offspring that are produced by selected offspring of a particular mating. We compare our criterion with other published criteria in a stochastic simulation of an ongoing breeding program for 21 generations for proof of concept. ExpBVSelGrOff performed better than all other tested criteria, like the usefulness criterion or Index5 which have been proposed in the literature, without compromising short-term gains. After only five generations, when selection is strong (1%), selection based on ExpBVSelGrOff achieved 5.8% more commercial genetic gain and retained 25% more genetic variance without compromising inbreeding rate compared to selection based only on breeding values. Our proposed selection criterion offers a new tool to accelerate genetic progress for contemporary genomic breeding programs. It retains more genetic variance than previously published criteria that plan less far ahead. Considering future gametic Mendelian sampling variances in the selection process also seems promising for maintaining more genetic variance.

中文翻译：

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通过考虑未来两代的孟德尔抽样方差，改进利用交配信息的选择决策


育种计划是根据用于传播遗传进展的动物的遗传水平来判断的。这些动物通常是种群中最好的。为了最大限度地提高下一代优秀动物的遗传水平，需要选择更有可能产生表现最好的后代的父母。由于育种值和配子变异的差异，个体产生高性能后代的能力也有所不同。个体之间配子变异的差异是由杂合性和连锁的差异引起的。配子孟德尔采样方差的使用之前已被提出，用于有用性标准或 Index5，在这项工作中，我们不仅考虑个体的配子孟德尔采样方差，而且还考虑其潜在后代的配子孟德尔采样方差，从而扩展现有方法。因此，本研究中制定的标准计划提前一代人。为简单起见，我们假设所有动物的真实数量性状位点（QTL）效应、遗传图谱和单倍型都是已知的。在这项研究中，我们提出了一个新的选择标准 ExpBVSelGrOff，它描述了由特定交配的选定后代产生的选定孙代的遗传水平。我们对正在进行的 21 代育种计划进行随机模拟，将我们的标准与其他已发布的标准进行比较，以进行概念验证。 ExpBVSelGrOff 的表现优于所有其他测试标准，例如文献中提出的有用性标准或 Index5，且不影响短期收益。仅经过 5 代，当选择很强（1%）时，基于 ExpBVSelGrOff 的选择达到了 5。与仅基于育种值的选择相比，在不影响近交率的情况下，商业遗传增益增加 8%，保留遗传变异增加 25%。我们提出的选择标准为加速当代基因组育种计划的遗传进展提供了一种新工具。与之前发布的标准相比，它保留了更多的遗传变异，而这些标准的计划不太远。考虑到选择过程中未来的配子孟德尔采样方差似乎也有望维持更多的遗传方差。