Genetic Basis of Morphological Evolution in the Drosophila bipectinata Species Complex

双梳状果蝇（Drosophila bipectinata）物种复合体形态进化的遗传基础，生物学中的一个关键挑战是了解表型进化和物种形成的遗传和分子机制。 DNA序列中的哪些变化是形态学创新的原因？ 这些变化如何影响发育并转化为表型多样性？ 是什么样的进化力量推动了这些变化？ 这些问题可以通过分析密切相关的物种之间表型差异的发育遗传基础来解决。 为了对这种类型的研究有用，模式物种必须表现出相当大的表型差异，但同时可以进行遗传分析。 这些条件在Drosophila bipectinata物种复合体中得到了完美的满足-这是一组与D.黑腹菌 bipectinata复合体的物种显示显着的变化，在性别二态形态特征，包括角质色素沉着和性梳形态。 双梳纲复合体是最近进化辐射的产物。 其成员物种之间的遗传距离很小，在圈养条件下很容易杂交。 Kopp博士将利用bipectinata复合体的这些特征来绘制负责色素沉着和性梳形态的种间和种内差异的基因;在分子水平上识别其中一些基因;测试是否相同的基因负责物种内和物种间的表型差异;表征候选基因的表达，并研究基因调控的进化变化是否是形态分歧的原因;并分析候选基因座的分子变异，鉴定可能导致形态学差异的DNA序列变化。 该项目的另一个重要成果将是开发一个新的模型系统，用于研究形态进化、生殖隔离、性选择和细分种群的遗传学。 为了实现这一目标，Kopp博士将开发两种bipectinata复合体的遗传和物理图谱，并保持一个收集的同基因，重组和突变的遗传菌株，将刺激未来的研究在这个模型。这项工作将产生广泛的影响，科学和社会，促进跨学科的研究生和本科生的培训。

Genetic basis of morphological evolution in the Drosophila bipectinata species complex.A key challenge in biology is to understand the genetic and molecular mechanisms of phenotypic evolution and speciation. What changes in DNA sequences are responsible for morphological innovations? How do these changes affect development and translate into phenotypic diversity? And what evolutionary forces promote these changes? These questions can best be addressed by analyzing the developmental genetic basis of phenotypic differences among closely related species. To be useful for this type of research, model species must show considerable phenotypic divergence, yet at the same time be accessible to genetic analysis. These conditions are met superbly in the Drosophila bipectinata species complex - a group of four closely related species that belong to the same lineage as D. melanogaster. Species of the bipectinata complex display dramatic variation in sexually dimorphic morphological traits, including cuticular pigmentation and sex comb morphology. The bipectinata complex is a product of a very recent evolutionary radiation. Its member species are separated by low genetic distances and hybridize easily in captivity. Dr. Kopp will use these features of the bipectinata complex to map the genes responsible for inter- and intraspecific divergence in pigmentation and sex comb morphology; to identify some of these genes at the molecular level; to test whether the same genes are responsible for phenotypic differences within and between species; to characterize the expression of candidate genes, and investigate whether evolutionary changes in gene regulation are responsible for morphological divergence; and to analyze molecular variation at candidate loci, and identify DNA sequence changes that may be responsible for morphological differences. Another important outcome of this project will be the development of a new model system for the study of morphological evolution, reproductive isolation, sexual selection, and the genetics of subdivided populations. Towards this goal, Dr. Kopp will develop genetic and physical maps for two species of the bipectinata complex, and maintain a collection of isogenic, recombinant, and mutant genetic strains that will stimulate future research in this model.This work will have a broad impact on science and society by promoting cross disciplinary training of graduate and undergraduate students.