MOLECULAR EVOLUTIONARY GENETICS OF HAWAIIAN DROSOPHILA CHORION

这是一个持续的研究项目，其目标是解决在夏威夷发生的果蝇进化和快速物种形成事件的一些理论。据推测，夏威夷果蝇的众多物种形成事件主要是重复的创始人事件与重复的辐射事件相结合的结果，这些辐射事件使它们适应了每个新兴火山岛中过多的空生态位。我们的目标是通过比较谱系的DNA分化率、种群内两两差异分布产生的曲线形状、它们的方差、每个种群的多态性水平与分化水平的比率，以及它们的密码子偏差的强度，来测试图片翼的planitibia亚群的β谱系是否经历了与α亚谱系相反的几个创始事件。此外，还将估计创始物种与其最近的祖先之间共享的多态性水平。一个岛屿内可能的早期物种之间共享的多态性水平将与被认为通过相同过程形成物种的兄弟物种的多态性水平进行比较。我们正在收集必要的数据，通过pcr介导扩增从野生捕获的苍蝇中提取的DNA片段，对应的两个绒毛膜基因具有快速的分化率和明显的中性进化。分子进化的中性模型将对这些片段进行检验。

This is a continuing program of research whose goal is to address some of the theories on the evolution and rapid Drosophila speciation events that have occurred in Hawaii. It has been postulated that the numerous speciation events in Hawaiian Drosophila are mostly a result of repetitive founder events combined with the repetitive radiation events towards forms adapted to a plethora of empty ecological niches in each emerging volcanic island. We aim to test if the beta lineages of the planitibia subgroup of the picture-wingeds have gone through several founder events as opposed to the alpha sub-lineage by comparing the DNA divergence rates of the lineages, the shape of the curves generated by the distributions of pairwise differences within populations, their variances, the ratio of the level of polymorphisms over divergence for each population, and the strength of their codon biases. In addition, the levels of polymorphisms shared between founder species and their closest ancestors will be estimated. The level of polymorphisms shared between presumable incipient species within an island will be compared to that of sibling species that are believed to have speciated by the same process. We are collecting the necessary data by the PCR-mediated amplification of DNA fragments extracted from wild-caught flies that correspond to two chorion genes with rapid divergence rates and apparent neutral evolution. The neutral model of molecular evolution will be tested for these fragments.