Molecular Phylogenetics and a Time Scale for Diversification of the Higher Flies (Diptera: Eremoneura)

Brian M. Wiegmann博士Brian Wiegmann和Jeffrey L.北卡罗来纳州州立大学的索恩获得了一笔赠款，用于研究一个经济上重要的昆虫群体的系统发育关系。 有近60，000个描述的物种，Eremoneura或更高的苍蝇（昆虫纲：双翅目：Brachycera），是最大和最成功的中生代年龄的昆虫辐射之一。 对形态学的解释引发了关于Eremeura内主要亚群之间关系的争论。两个主要的eremoneuran组，Empidoidea和Cyclorrhapha的基础谱系，一直特别有争议。尽管最近的关注，没有分子研究尚未解决eremoneuran分类。这个合作项目将综合形态学和分子证据来重建基底神经元进化的时间和模式。最近提出的方法估计分歧时间从核苷酸序列数据不需要生物学上难以置信的假设，分子进化的速率是恒定的。 这种估算发散时间的方法很有前途，但尚未得到充分的评价或改进。 在这个项目中阐明的Eremoneuran关系，以及最近的化石证据汇编将作为新方法估计分歧时间的能力的测试系统。 将进行分析，以：1）测试已发表的关于Eremoneura的基本科群关系的假设，2）测试Empidoidea的单系性及其作为Cyclorrhapha的姐妹群的位置，3）重建Eremoneura的分歧时间并测试分歧时间估计方法对不同基因和树拓扑结构的鲁棒性，双翅目是遗传、发育和进化生物学的模式系统，因此，双翅目的分子生物学和重建的时间尺度将是非常有价值的。 整合的分子和形态学证据brachyceran hepatogeny最终将提供一个框架，揭示模式和主要的中生代年龄的昆虫辐射相关的原因。

DEB-0089745Brian M. WiegmannDrs. Brian Wiegmann and Jeffrey L. Thorne of North Carolina State University have been awarded a grant to study phylogenetic relationships of an economically important instect group. With nearly 60,000 described species, the Eremoneura, or higher-flies (Insecta: Diptera: Brachycera), are among the largest and most successful of Mesozoic-aged insect radiations. Conflicting morphological interpretations have fueled a debate over the relationships of the major subgroups within Eremoneura. The basal lineages of the two major eremoneuran groups, Empidoidea and Cyclorrhapha, have been particularly controversial. Despite recent attention, no molecular studies have yet addressed eremoneuran classification. This collaborative project will synthesize morphological and molecular evidence to reconstruct the timing and pattern of basal eremoneuran evolution. Recently proposed methods for estimating divergence times from nucleotide sequence data do not require the biologically implausible assumption that rates of molecular evolution are constant over time. Such methods for estimating divergence times are promising but have not yet received adequate evaluation or refinement. Eremoneuran relationships that are elucidated within this project, and recent compilations of fossil evidence will serve as a test system for the ability of new methods to estimate divergence times. Analyses will be carried out to: 1) test published hypotheses for the basal family-group relationships of Eremoneura, 2) test the monophyly of the Empidoidea and its position as proposed sister-group to the Cyclorrhapha, 3) reconstruct eremoneuran divergence times and test the robustness of divergence time estimation methods to differing genes and tree topologies, Molecular phylogenies and a reconstructed time scale for eremoneuran Diptera will be extremely valuable because Diptera are model systems for genetic, developmental, and evolutionary biology. Integration of molecular and morphological evidence on brachyceran phylogeny will ultimately provide a framework for uncovering patterns and causes associated with major Mesozoic-aged insect radiations.