MOLECULAR POPULATION GENETICS OF DROSOPHILA MELANOGASTER

拟议的实验旨在检查水平、性质、 自然发生的DNA序列变异的组织和意义 在果蝇的两个大的、特征良好的黑腹果蝇区域 基因组(玫瑰王牌区域和双胸复合体)。四个嵌套级别为 建议。第一个涉及检查三个大样本的染色体。 从自然种群中提取的DNA序列的可变性 使用四个六碱基限制性内切酶。要研究的地区 是第三条染色体的315kb玫瑰王牌区域，以及附近的 400kb的Bithorax复合体。要解决的问题包括：1)是否有 在一个区域的转录活性和 核苷酸水平和/或插入/缺失多态？2)是否有 可转座元件的插入热点的证据？3)情况如何 不同基因的变异是沿着序列组织的？是非随机的 与功能相关基因簇相关的关联？4) 非随机关联的模式是否反映了 通过这些区域的重组？第二级考试将 对玫瑰花基因进行四碱基限制性内切酶分析。这一方法将 允许检查10kb中约20%的核苷酸 区里有几百条线。该项目的第三级将是 问一问DNA水平上的变异与DNA水平上的变异 “表型”水平通过量化玫瑰和王牌的表达水平。 将选出20个单倍型、等位酶和活性差异较大的品系 用于XDH的完整DNA测序(4级)。这些数据将允许更多 对上述问题1、3和4的精炼答案以及贡献 基因内重组对等位基因多样性分离的影响 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.