MOLECULAR EVOLUTIONARY GENETICS OF HAWAIIAN DROSOPHILA CHORION

这是一个持续的研究项目，其目标是解决夏威夷发生的一些关于果蝇进化和快速物种形成事件的理论。据推测，夏威夷果蝇中的大量物种形成事件主要是由于重复的创始人事件和针对适应于每个新兴火山岛上过多的空生态位的形式的重复辐射事件的结果。我们的目标是通过比较谱系的DNA分歧率、由群体内成对差异分布产生的曲线的形状、它们的方差、每个群体的多态与分歧水平的比率以及它们的密码子偏向的强度，来测试画翼类的Plantitibia亚群的Beta谱系是否经历了几次创始人事件，而不是Alpha亚谱系。此外，还将估计创始人物种及其最接近的祖先之间共享的多态水平。一个岛屿内假定的初始物种之间共享的多态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水平进行比较。我们正在通过从野生捕获的苍蝇中提取的DNA片段的PCR介导的扩增来收集必要的数据，这两个基因对应于两个具有快速分歧率和明显的中性进化的绒毛膜基因。分子进化的中性模型将对这些片段进行测试。

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.