Frisch Matthias, Melchinger Albrecht E
Institute of Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, 70593 Stuttgart, Germany.
Genetics. 2006 Oct;174(2):795-803. doi: 10.1534/genetics.106.057273. Epub 2006 Aug 3.
Molecular markers can be employed to predict the parental genome contribution to inbred lines. The proportion alpha of alleles originating from parent P1 at markers polymorphic between the parental lines P1 and P2 is commonly used as a predictor for the genome contribution of parent P1 to an offspring line. Our objectives were to develop a new marker-based predictor xi for the parental genome contribution, which takes into account not only the alleles at marker loci but also their map distance, and to compare the prediction precision of xi with that of alternative methods. We derived formulas for xi for inbreds derived from biparental crosses (F1 and backcrosses) with the single-seed descent or double-haploid method and presented an extension xi* possessing statistical optimum properties. In a simulation study, alpha showed a systematic overestimation of large parental genome contribution that was not observed for xi. The mean squared prediction error of xi was at least 50% smaller than that of alpha for linkage maps with unequal distances between adjacent markers. A data set from a study on plant variety protection in maize was used to illustrate the application of xi. We conclude that xi provides substantially greater prediction precision than the commonly used predictor alpha in a broad range of applications in genetics and breeding.
分子标记可用于预测亲本基因组对自交系的贡献。在亲本系P1和P2之间多态的标记位点上，源自亲本P1的等位基因比例α通常被用作亲本P1对后代系基因组贡献的预测指标。我们的目标是开发一种基于标记的新预测指标ξ，用于预测亲本基因组贡献，该指标不仅考虑标记位点的等位基因，还考虑其图谱距离，并将ξ与其他方法的预测精度进行比较。我们推导了通过单粒传法或双单倍体法从双亲杂交（F1和回交）获得的自交系的ξ公式，并提出了具有统计最优性质的扩展指标ξ*。在一项模拟研究中，α对亲本基因组较大贡献存在系统性高估，而ξ未出现这种情况。对于相邻标记间距离不等的连锁图谱，ξ的预测均方误差比α至少小50%。利用一项关于玉米品种保护研究的数据集来说明ξ的应用。我们得出结论，在遗传学和育种的广泛应用中，ξ比常用的预测指标α具有更高的预测精度。
