Mackinnon M J, Weller J I
Institute of Cell, Animal and Population Biology, University of Edinburgh, United Kingdom.
Genetics. 1995 Oct;141(2):755-70. doi: 10.1093/genetics/141.2.755.
Maximum likelihood methods were developed for estimation of the six parameters relating to a marker-linked quantitative trait locus (QTL) segregating in a half-sib design, namely the QTL additive effect, the QTL dominance effect, the population mean, recombination between the marker and the QTL, the population frequency of the QTL alleles, and the within-family residual variance. The method was tested on simulated stochastic data with various family structures under two genetic models. A method for predicting the expected value of the likelihood was also derived and used to predict the lower bound sampling errors of the parameter estimates and the correlations between them. It was found that standard errors and confidence intervals were smallest for the population mean and variance, intermediate for QTL effects and allele frequency, and highest for recombination rate. Correlations among standard errors of the parameter estimates were generally low except for a strong negative correlation (r = -0.9) between the QTL's dominance effect and the population mean, and medium positive and negative correlations between the QTL's additive effect and, respectively, recombination rate (r = 0.5) and residual variance (r = -0.6). The implications for experimental design and method of analysis on power and accuracy of marker-QTL linkage experiments were discussed.
最大似然法被用于估计在半同胞设计中分离的与标记连锁的数量性状基因座（QTL）相关的六个参数，即QTL加性效应、QTL显性效应、群体均值、标记与QTL之间的重组率、QTL等位基因的群体频率以及家系内残差方差。该方法在两种遗传模型下，对具有不同家系结构的模拟随机数据进行了测试。还推导了一种预测似然期望值的方法，并用于预测参数估计值的下限抽样误差及其之间的相关性。结果发现，群体均值和方差的标准误差和置信区间最小，QTL效应和等位基因频率的居中，重组率的最高。除了QTL显性效应与群体均值之间存在强负相关（r = -0.9），以及QTL加性效应分别与重组率（r = 0.5）和残差方差（r = -0.6）之间存在中等程度的正负相关外，参数估计值的标准误差之间的相关性一般较低。讨论了对标记-QTL连锁实验的功效和准确性的实验设计及分析方法的影响。
