Noor M A, Schug M D, Aquadro C F
Section of Genetics and Development, Cornell University, Ithaca, New York, USA.
Genet Res. 2000 Feb;75(1):25-35. doi: 10.1017/s0016672399004024.
We have isolated, characterized and mapped 33 dinucleotide, three trinucleotide and one tetranucleotide repeat loci from the four major chromosomes of Drosophila pseudoobscura. Average inferred repeat unit length of the dinucleotide repeats is 12 repeat units, similar to D. melanogaster. Assays of D. pseudoobscura and populations of its sibling species, D. persimilis, using 10 of these loci show extremely high levels of variation compared with similar studies of dinucleotide repeat variation in D. melanogaster populations. The high levels of variation are consistent with an average mutation rate of approximately 10(-6) per locus per generation and an effective population size of D. pseudoobscura approximately four times larger than that of D. melanogaster. Consistent with allozymes and nucleotide sequence polymorphism, the dinucleotide repeat loci reveal minimal structure across four populations of D. pseudoobscura. Finally, our preliminary recombinational mapping of 24 of these microsatellites suggests that the total recombinational genome size may be larger than previously inferred using morphological mutant markers.
我们从拟暗果蝇的四条主要染色体中分离、鉴定并定位了33个二核苷酸、3个三核苷酸和1个四核苷酸重复位点。二核苷酸重复序列的平均推断重复单元长度为12个重复单元，与黑腹果蝇相似。使用其中10个位点对拟暗果蝇及其近缘种果蝇进行检测，结果表明，与黑腹果蝇群体中二核苷酸重复变异的类似研究相比，其变异水平极高。这种高变异水平与每个位点每代约10(-6)的平均突变率以及拟暗果蝇的有效种群大小比黑腹果蝇大约四倍相一致。与等位酶和核苷酸序列多态性一致，二核苷酸重复位点在拟暗果蝇的四个种群中显示出最小的结构。最后，我们对其中24个微卫星的初步重组定位表明，总的重组基因组大小可能比以前使用形态突变标记推断的要大。
