Minor differences in haplotype frequency estimates can produce very large differences in heterogeneity test statistics.
Minor differences in haplotype frequency estimates can produce very large differences in heterogeneity test statistics.
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DOI：
10.1186/1471-2156-8-38
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发表时间：
2007-06-27
期刊：
影响因子：
2.9
通讯作者：
Xu, Ke
中科院分区：
文献类型：
--
作者：
Curtis, David;Xu, Ke
单倍型和疾病之间的关联的测试通常使用病例和对照单倍型频率之间的异质性的似然比测试来进行。使用海洛因依赖与DRD 2基因之间关联研究的数据，我们使用两种不同的计算机程序MLOCUS和GENECOUNTING获得了估计的单倍型频率和相关的似然比统计量。我们还进行了排列测试，以评估所获得的结果的经验意义。这两个程序产生了相似的，但不完全相同，估计单倍型频率。MLOCUS产生的p值为1.8*10-15，GENECOUNTING产生的p值为5.4*10-4。排列检验产生的p值为2.8*10-4。两个程序的似然比统计值之间存在非常大的差异，这一事实可能反映了这样一个事实，即合并组的单倍型频率不受限制，不等于病例和对照组频率的加权平均值，因为如果直接观察而不是估计，它们就会被限制。单倍型频率估计值的微小差异可能导致似然比统计量和相关p值的非常大的差异。
Tests for association between a haplotype and disease are commonly performed using a likelihood ratio test for heterogeneity between case and control haplotype frequencies. Using data from a study of association between heroin dependence and the DRD2 gene, we obtained estimated haplotype frequencies and the associated likelihood ratio statistic using two different computer programs, MLOCUS and GENECOUNTING. We also carried out permutation testing to assess the empirical significance of the results obtained. Both programs yielded similar, though not identical, estimates for the haplotype frequencies. MLOCUS produced a p value of 1.8*10-15 and GENECOUNTING produced a p value of 5.4*10-4. Permutation testing produced a p value 2.8*10-4. The fact that very large differences occur between the likelihood ratio statistics from the two programs may reflect the fact that the haplotype frequencies for the combined group are not constrained to be equal to the weighted averages of the frequencies for the cases and controls, as they would be if they were directly observed rather than being estimated. Minor differences in haplotype frequency estimates can result in very large differences in the likelihood ratio statistic and associated p value.
影响因子：
1.9
作者：
Curtis, D;Knight, J;Sham, PC
通讯作者：
Sham, PC
影响因子：
--
作者：
Xu, K;Lichtermann, D;Goldman, D
通讯作者：
Goldman, D
影响因子：
5.8
作者：
Zhao, JH;Lissarrague, S;Sham, PC
通讯作者：
Sham, PC