Schug M D, Mackay T F, Aquadro C F
Section of Genetics and Development, Cornell University, Ithaca, New York 14853, USA.
Nat Genet. 1997 Jan;15(1):99-102. doi: 10.1038/ng0197-99.
Analysis of variation at microsatellite DNA loci is widely used in studies of parentage, linkage and evolutionary history. The utility of microsatellites is primarily due to high levels of allelic diversity, believed to reflect mutation rates orders of magnitude higher than base pair substitutions at single-copy genes. For humans, mice, rats and pigs, microsatellite mutation rates have been estimated at 10(-3)-10(-5). However, a recent study comparing microsatellite variation in humans with non-human primates suggests that microsatellite mutation rates may vary considerably across taxa. We measured mutation rates of 24 microsatellite loci in mutation accumulation lines of Drosophila melanogaster. Surprisingly, only a single mutation was detected after screening 157,680 allele-generations, yielding an estimated average mutation rate per locus of 6.3 x 10(-6), a mutation rate considerably lower than reported for various mammals. We propose that the comparatively low mutation rate is primarily a function of short microsatellite repeat lengths in the D. melanogaster genome.
微卫星DNA位点变异分析广泛应用于亲子关系、连锁和进化史研究。微卫星的效用主要归因于其高度的等位基因多样性，据信这反映出其突变率比单拷贝基因中的碱基对替换高几个数量级。对于人类、小鼠、大鼠和猪，微卫星突变率估计为10^(-3)-10^(-5)。然而，最近一项比较人类与非人类灵长类动物微卫星变异的研究表明，微卫星突变率可能在不同分类群中差异很大。我们测量了黑腹果蝇突变积累系中24个微卫星位点的突变率。令人惊讶的是，在筛选了157,680个等位基因世代后仅检测到一个突变，每个位点的估计平均突变率为6.3×10^(-6)，该突变率远低于各种哺乳动物的报道值。我们认为，相对较低的突变率主要是黑腹果蝇基因组中微卫星重复长度较短的结果。
