Wilson A F, Elston R C
Department of Biometry and Genetics, Louisiana State University Medical Center, New Orleans 70112.
Genet Epidemiol. 1993;10(6):593-8. doi: 10.1002/gepi.1370100644.
Simulation experiments were used to determine the empiric type I error rate of the Haseman-Elston sib-pair test for linkage between a quantitative trait and a marker locus in samples with 60 or fewer sib pairs. The effect of different levels of marker-locus heterozygosity on statistical validity was also considered. The test was performed on the trait and each of five unlinked markers, and evaluated using two different degrees of freedom for the t-distribution. The number of degrees of freedom in the first evaluation was based on the number of sib pairs in each sibship, sigma s(i)(s(i) - 1)/2 - 2. In the second evaluation, the number of degrees freedom was based on the number of sibs minus 1 in each sibship, sigma (s(i) - 1) - 2. Empirically determined type I error rates using sigma s(i)(s(i) - 1)/2 - 2 degrees of freedom were slightly liberal. For sigma (s(i) - 1) - 2 degrees of freedom, the estimated empiric p-values were nearly identical to their respective nominal p-values. Decreasing levels of heterozygosity did not increase the empiric type I error rate when the sample size was small.
采用模拟实验来确定在同胞对数为60对或更少的样本中，用于定量性状与标记位点之间连锁分析的Haseman-Elston同胞对检验的经验性I型错误率。同时还考虑了不同水平的标记位点杂合性对统计有效性的影响。对该性状和五个不连锁的标记分别进行检验，并使用t分布的两种不同自由度进行评估。第一次评估中的自由度基于每个同胞组中的同胞对数，即∑s(i)(s(i) - 1)/2 - 2。在第二次评估中，自由度基于每个同胞组中的同胞数减1，即∑(s(i) - 1) - 2。使用∑s(i)(s(i) - 1)/2 - 2自由度通过经验确定的I型错误率略宽松。对于∑(s(i) - 1) - 2自由度，估计的经验性p值与其各自的名义p值几乎相同。当样本量较小时，杂合性水平降低并未增加经验性I型错误率。
