A DISEQUILIBRIUM COEFFICIENT APPROACH TO HARDY-WEINBERG TESTING
A DISEQUILIBRIUM COEFFICIENT APPROACH TO HARDY-WEINBERG TESTING
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DOI：
10.2307/2532034
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发表时间：
1989-03-01
期刊：
影响因子：
1.9
通讯作者：
WEIR, BS
中科院分区：
文献类型：
--
作者：
HERNANDEZ, JL;WEIR, BS
对Hardy-Weinberg平衡的各种检验方法进行了比较，重点介绍了复等位基因的检验方法。对于偏离平衡的总体检验，经典的卡方拟合优度检验通常表现良好，对于极端基因频率或极端偏离平衡需要进行连续性校正。对于小样本，概率检验是优选的，并且对于多个等位基因，可以对具有固定的样本基因频率组的所有可能的基因型频率组的样本进行那些概率检验。数值计算表明，连续性校正卡方是最保守的测试程序，和未校正卡方最不保守。对于多个等位基因，通过使用不平衡系数，可以更好地理解偏离平衡的性质，不平衡系数定义为每个杂合子的观察频率和预期频率之间的差异。似然比检验可用于单独检验这些系数中的每一个，但令人满意的程序是将每个系数的平方估计值除以其估计方差，并将该比率视为单自由度卡方。数值研究证实了这种方法的有效性，它具有不需要非线性方程的解决方案的巨大优势。
A comparison was made of various tests for Hardy-Weinberg equilibrium, with emphasis on methods for multiple alleles. For an overall test of deviations from equilibrium, the classical chi-square goodness-of-fit test generally performs well, with continuity corrections needed for extreme gene frequencies or extreme departures from equilibrium. For small samples, probability tests are preferable and for multiple alleles those probability tests may be performed on a sample of all possible sets of genotypic frequencies having a fixed set of sample gene frequencies. Numerical work showed that the continuity-corrected chi-square was the most conservative test procedure, and the uncorrected chi-square the least conservative. With multiple alleles, a better appreciation of the nature of departures from equilibrium is given by the use of disequilibrium coefficients, defined for each heterozygote as the difference between observed and expected frequencies. Likelihood-ratio tests can be used to test each of these coefficients individually but a satisfactory procedure is to divide the squared estimate of each coefficient by its estimated variance and regard the ratio as a single-degree-of-freedom chi-square. Numerical studies confirmed the validity of this approach, which has the great advantage of not requiring solutions of nonlinear equations.