Crop Development Centre, University of Saskatchewan, S7N 0WO, Saskatoon, Saskatchewan, Canada.
Theor Appl Genet. 1985 Mar;69(5-6):559-66. doi: 10.1007/BF00251104.
Computer simulation of several genetic models was used to assess the effect of type I and type II statistical errors on estimating the number of genes by the inbred-backcross and genotype assay procedures. Depending upon the actual number of genes, heritability, and the probability of type I errors (α), substantial upward and downward biases were observed in estimates of the number of genes from both methods. The estimated number of genes increased as α was increased from 0.01 to 0.30 and as heritability increased. With high α and/or high heritability, the estimated number of genes often exceeded the actual number. Downward biases occurred with low α and low heritability, and tended to become greater as the number of genes in the model was increased. Large type II errors were associated with downward biases. The choice of α had a greater impact on biases in estimates from the genotype assay procedure than from the inbred-backcross procedure. Increasing the number of backcrosses in the inbred-backcross procedure or delaying the assay generation in genotype assay increased the probability of upward biases in the estimated number of genes. Unbiased estimates can be obtained only by choice of an optimum α. There is no known way to choose the optimum α in practice. This fact reduces the value of estimates of the number of genes by genotype assay or by the inbred-backcross methods.
使用计算机模拟了几种遗传模型，以评估 I 型和 II 型统计误差对通过近交回交和基因型检测程序估计基因数量的影响。根据实际基因数量、遗传力和 I 型错误（α）的概率，两种方法估计的基因数量都存在较大的向上和向下偏差。随着α从 0.01 增加到 0.30 和遗传力增加，估计的基因数量增加。当α高且/或遗传力高时，估计的基因数量通常超过实际数量。当α低且遗传力低时，向下偏差发生，并且随着模型中基因数量的增加，偏差往往会更大。大的 II 型错误与向下偏差有关。α的选择对基因型检测程序估计值的偏差的影响大于对近交回交程序估计值的偏差的影响。增加近交回交程序中的回交次数或延迟基因型检测的检测世代，会增加估计基因数量的向上偏差的概率。只有通过选择最佳的α，才能获得无偏估计。在实践中，目前还没有选择最佳α的方法。这一事实降低了通过基因型检测或近交回交方法估计基因数量的估计值的价值。
