Hilliker A J, Clark S H, Chovnick A
Department of Molecular Biology and Genetics, University of Guelph, Ontario, Canada.
Genetics. 1991 Nov;129(3):779-81. doi: 10.1093/genetics/129.3.779.
The effect of simple DNA sequence polymorphisms on intragenic recombination in the rosy locus of Drosophila melanogaster was assayed. Two crosses were performed involving nearly identical molecular distances between selective ry null mutations (3778 nucleotides and 3972 nucleotides). In one heterozygote (ry606/ry531), in addition to the nucleotide substitution ry- mutations, there were 11 simple nucleotide polymorphisms between the selective markers as well as additional flanking simple nucleotide polymorphisms within the rosy locus. In the other heterozygote (ry606/ry609), there were no additional polymorphisms because the two rosy nucleotide substitution mutations were induced on the same rosy isoallele (ry+6). From ry606/ry531 heterozygous females, 27 intragenic crossovers and five marker conversions were seen among 4.53 x 10(5) progeny. From ry606/ry609 heterozygous females, 23 intragenic crossovers and eight marker conversions were seen among 4.18 x 10(5) progeny. The intragenic crossover frequencies per kilobase of DNA were very similar, 1.6 x 10(-5) for ry606/ry531 and 1.4 x 10(-5) for ry606/ry609. Thus, simple DNA sequence polymorphisms neither inhibit nor promote intragenic recombination in D. melanogaster.
检测了简单DNA序列多态性对黑腹果蝇 rosy 基因座内基因内重组的影响。进行了两个杂交实验，涉及选择性 ry 无效突变之间几乎相同的分子距离（3778个核苷酸和3972个核苷酸）。在一个杂合子（ry606/ry531）中，除了核苷酸替代ry - 突变外，选择性标记之间还有11个单核苷酸多态性，以及 rosy 基因座内额外的侧翼单核苷酸多态性。在另一个杂合子（ry606/ry609）中，没有额外的多态性，因为两个 rosy 核苷酸替代突变是在同一个 rosy 等位基因（ry + 6）上诱导产生的。在ry606/ry531杂合雌性的4.53×10⁵ 后代中，观察到27次基因内交叉和5次标记转换。在ry606/ry609杂合雌性的4.18×10⁵ 后代中，观察到23次基因内交叉和8次标记转换。每千碱基DNA的基因内交叉频率非常相似，ry606/ry531为1.6×10⁻⁵，ry606/ry609为1.4×10⁻⁵。因此，简单DNA序列多态性既不抑制也不促进黑腹果蝇的基因内重组。
