Vitellogenin Genes in Hawaiian Drosophila: A Paradigm for Molecular Analyses of Evolution

夏威夷群岛特有的果蝇种群为研究进化和生态适应提供了理想的天然实验室。这些不同种类的夏威夷苍蝇的卵黄蛋白原或卵黄蛋白基因组成了一个特殊的模型系统，用于分析高等生物的基因进化机制和速度。这个基因簇的成员编码三种卵黄蛋白原蛋白，受到严格的发育调控，控制着卵黄蛋白原合成的时机、组织特异性和合成速度，以协调每个物种与其特定生态环境的卵子成熟。拟议的研究将使用最新发展的分子生物学技术，以加快确定这些基因在九个物种中的DNA序列，并分析两个物种种群内和种群之间的序列变异水平。DNA序列比较将确定卵黄蛋白原基因结构和功能种间差异的分子基础。物种间的基因变化将与寄主植物和繁殖策略的适应性变化有关，目的是区分不同类型的DNA序列在物种进化中所起的作用。对使用编码差异和对照序列构建的系统发育图的比较将检验这样一个假设，即基因组中的调节变化与适应性和系统发育变化更紧密地一致。

The Hawaiian Islands with their populations of endemic Drosophila species provide an ideal natural laboratory for studying evolution and ecological adaptations. The vitellogenin or yolk protein genes of these diverse Hawaiian flies comprise an exceptional model system for analyzing mechanisms and rates of gene evolution in higher organisms. The members of this gene cluster, encoding three vitellogenin proteins, are subject to strict developmental regulation, which controls timing, tissue- specificity and rates of vitellogenin synthesis to coordinate egg maturation of each species with its particular ecological habitat. The proposed research will use the most recently developed techniques of molecular biology to expedite determination of DNA sequences of these genes in nine species and assay levels of sequence variation within and between populations of two species. DNA sequence comparisons will identify the molecular basis of interspecific differences in vitellogenin gene structure and function. Gene changes between species will be related to adaptive shifts in host plants and reproductive strategies, the goal being to distinguish the roles played by various types of DNA sequences in species evolution. Comparisons of phylogenies constructed using divergence in coding versus control sequences will test the hypothesis that regulatory changes in the genome are more closely aligned with adaptive and phylogenetic change.