Genetic Basis of Morphological Evolution in the Drosophila bipectinata Species Complex

点击翻译按钮获取中文摘要

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.