连锁不平衡的抽样分布。
The sampling distribution of linkage disequilibrium.
作者信息
Golding G B
出版信息
Genetics. 1984 Sep;108(1):257-74. doi: 10.1093/genetics/108.1.257.
The probabilities of obtaining particular samples of gametes with two completely linked loci are derived. It is assumed that the population consists of N diploid, randomly mating individuals, that each of the two loci mutate according to the infinite allele model at a rate mu and that the population is at equilibrium. When 4N mu is small, the most probable samples of gametes are those that segregate only two alleles at either locus. The probabilities of various samples of gametes are discussed. The results show that most samples with completely linked loci have either a very small or a very large association between the alleles of each locus. This causes the distribution of linkage disequilibrium to be skewed and the distribution of the correlation coefficient to be bimodal. The correlation coefficient is commonly used as a test statistic with a chi square distribution and yet has a bimodal distribution when the loci are completely linked. Thus, such a test is not likely to be accurate unless the rate of recombination between the loci and/or the effective population size are sufficiently large enough so that the loci can be treated as unlinked.
推导出了具有两个完全连锁基因座的特定配子样本的概率。假设群体由N个二倍体、随机交配的个体组成，两个基因座中的每一个都根据无限等位基因模型以速率μ发生突变，并且群体处于平衡状态。当4Nμ较小时，最可能的配子样本是那些在任一基因座仅分离两个等位基因的样本。讨论了各种配子样本的概率。结果表明，大多数具有完全连锁基因座的样本在每个基因座的等位基因之间要么具有非常小的关联，要么具有非常大的关联。这导致连锁不平衡的分布呈偏态，相关系数的分布呈双峰态。相关系数通常用作具有卡方分布的检验统计量，但当基因座完全连锁时，它具有双峰分布。因此，除非基因座之间的重组率和/或有效群体大小足够大，使得基因座可以被视为不连锁，否则这样的检验不太可能准确。
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