The mutation rates of di-, tri- and tetranucleotide repeats in Drosophila melanogaster
The mutation rates of di-, tri- and tetranucleotide repeats in Drosophila melanogaster
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DOI：
10.1093/oxfordjournals.molbev.a025901
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发表时间：
1998-12-01
影响因子：
10.7
通讯作者：
Aquadro, CF
中科院分区：
文献类型：
--
作者：
Schug, MD;Hutter, CM;Aquadro, CF
在最近的一项研究中，我们报道了黑腹果蝇（Drosophila melanogaster）中10个二核苷酸、6个三核苷酸和8个四核苷酸重复序列的组合平均突变率为每一代每个位点6.3 X 10（-6）个突变，大大低于迄今为止研究的哺乳动物的微卫星重复单元(范围为每一代每个位点10（-2)-10（-5）个）。为了获得更精确的二核苷酸重复基序突变率，我们分析了先前研究中突变积累系中39个新的二核苷酸重复微卫星位点。我们对49个二核苷酸重复序列的突变率估计为每一代9.3 x 10（-6）个位点，仅略高于我们早期研究的估计。我们还使用基于群体变异的方法估计了黑腹龙脑基因组中二核苷酸、三核苷酸和四核苷酸重复序列的微卫星突变率的相对差异，发现三核苷酸和四核苷酸重复序列的突变率分别比二核苷酸重复序列慢6.4倍和8.4倍。三核苷酸和四核苷酸重复序列较慢的突变率似乎与黑腹龙基因组中这些重复序列的重复单位长度相对较短有关。重复单位长度与等位基因变异呈正相关，表明微卫星的突变率随着重复单位长度的增加而增加。
In a recent study, we reported that the combined average mutation rate of 10 di-, 6 tri-, and 8 tetranucleotide repeats in Drosophila melanogaster was 6.3 X 10(-6) mutations per locus per generation, a rate substantially below that of microsatellite repeat units in mammals studied to date (range = 10(-2)-10(-5) per locus per generation). To obtain a more precise estimate of mutation rate for dinucleotide repeat motifs alone, we assayed 39 new dinucleotide repeat microsatellite loci in the mutation accumulation lines from our earlier study. Our estimate of mutation rate for a total of 49 dinucleotide repeats is 9.3 x 10(-6) per locus per generation, only slightly higher than the estimate from our earlier study. We also estimated the relative difference in microsatellite mutation rate among di-, tri-, and tetranucleotide repeats in the genome of D. melanogaster using a method based on population variation, and we found that tri- and tetranucleotide repeats mutate at rates 6.4 and 8.4 times slower than that of dinucleotide repeats, respectively. The slower mutation rates of tri- and tetranucleotide repeats appear to be: associated with a relatively short repeat unit length of these repeat motifs in the genome of D. melanogaster. A positive correlation between repeat unit length and allelic variation suggests that mutation rate increases as the repeat unit lengths of microsatellites increase.