MOLECULAR POPULATION GENETICS OF DROSOPHILA MELANOGASTER

拟议的实验旨在研究水平，性质， 自然发生的DNA序列变异的组织和意义 在黑腹果蝇的两个大的、特征明确的区域， 基因组（rosy-Ace区域和双胸复合体）。 四个嵌套级别是 提出了 第一项研究涉及检查三个大的染色体样本 从D. DNA序列变异性 使用四种六碱基限制性内切酶。 研究区域 是第三条染色体的315 kb rosy-Ace区域，以及附近的 400\kb双胸复合体。 需要解决的问题包括：1） 一个区域的转录活性与 核苷酸和/或插入/缺失多态性水平？ 2)有没有 转座因子插入热点的证据 3)怎么样 不同基因沿着排列的变异？ 都是非随机的 与功能相关基因簇相关的关联？ 四、 非随机关联的模式是否反映了 通过这些区域重组？ 第二级考试将 通过对Rosy位点的四碱基限制性分析。 这种方法将 允许检测10 kb中约20%的核苷酸 在几百条线上。 该项目的第三个层面将是 问在DNA水平上的变异是如何与 通过定量rosy和Ace的表达水平来确定“表型”水平。 将选出20个具有不同单倍型、等位酶和活性的品系 用于Xdh的完整DNA测序（4级）。 这些数据将使更多 对上述问题1、3和4的精确答复以及对 基因内重组的等位基因多样性分离在自然 人口。

The proposed experiments are designed to examine the level, nature, organization and significance of naturally occurring DNA sequence variation in two large, well characterized regions of the Drosophila melanogaster genome (rosy-Ace region and Bithorax Complex). Four nested levels are proposed. The first involves examining three large samples of chromosomes from natural populations of D. melanogaster for DNA sequence variability using four six-base restriction endonucleases. The regions to be studied are the 315 kb rosy-Ace region of the third chromosome, and the nearby 400\kb Bithorax Complex. Questions to be addressed include: 1) Does a correlation exist between transcriptional activity of a region and the level of nucleotide and/or insertion/deletion polymorphism? 2) Is there evidence of insertional hotspots for transposable elements? 3) How is the variation at different genes along the sequence organized? Are nonrandom associations associated with clusters of functionally related genes? 4) Does the pattern of nonrandom association reflect variation in the rates of recombination through these regions? The second level of examination will be by four-base restriction analysis of the rosy locus. This approach will allow the examination of approximately 20% of the nucleotides in a 10 kb region in several hundred lines. The third level of the project will be to ask how variation at the DNA level is related to variation at the "phenotypic" level by quantitating levels of expression for rosy and Ace. Twenty lines of divergent haplotype, allozyme and activity will be selected for complete DNA sequencing of Xdh (level 4). These data will allow more refined answers to questions 1, 3 and 4 above as well as the contribution of intragenic recombination to allelic diversity segregating in natural populations.