Equilibrium distributions of microsatellite repeat length resulting from a balance between slippage events and point mutations
Equilibrium distributions of microsatellite repeat length resulting from a balance between slippage events and point mutations
复制标题
DOI：
10.1073/pnas.95.18.10774
复制
发表时间：
1998-09-01
影响因子：
11.1
通讯作者：
Aquadro, CF
中科院分区：
文献类型：
--
作者：
Kruglyak, S;Durrett, RT;Aquadro, CF
我们描述并测试了微卫星进化的马尔可夫链模型，该模型可以解释微卫星长度在不同生物体和重复基序中的不同分布。该模型的两个关键特征是突变率依赖于微卫星长度，以及包括链滑移和点突变事件的突变过程。我们在该模型下计算了等位基因长度的平稳分布，并用它来拟合人类、小鼠、果蝇和酵母中二、三、四核苷酸重复序列的DNA数据。最佳拟合结果导致滑动率估计值在小鼠中最高，其次是人类，然后是酵母，然后是果蝇。在每种生物体中，二、三、四核苷酸重复序列的估计值最高。我们的估计与其他研究中实验确定的突变率一致。结果表明，生物和重复基序之间的不同长度分布可以用滑动率的简单差异来解释，并且不需要对长度施加选择性限制。
We describe and test a Markov chain model of microsatellite evolution that can explain the different distributions of microsatellite lengths across different organisms and repeat motifs, Two key features of this model are the dependence of mutation rates on microsatellite length and a mutation process that includes both strand slippage and point mutation events. We compute the stationary distribution of allele lengths under this model and use it to fit DNA data for di-, tri-, and tetranucleotide repeats in humans, mice, fruit flies, and yeast, The best fit results lead to slippage rate estimates that are highest in mice, followed by humans, then yeast, and then fruit flies, Within each organism, the estimates are highest in di-, then tri-, and then tetranucleotide repeats. Our estimates are consistent with experimentally determined mutation rates from other studies. The results suggest that the different length distributions among organisms and repeat motifs can be explained by a simple difference in slippage rates and that selective constraints on length need not be imposed.