Comparative Genomics Insights into Speciation and Evolution of Hawaiian Drosophila

Speciation and adaptation have always been of great interest to biologists. The Hawaiian archipelago provides a natural arena for understanding adaptive radiation and speciation, and genomics and bioinformatics offer new approaches for studying these fundamental processes. The mode of speciation should have profound impacts on the genomic architecture and patterns of reproductive isolation of new species. The Hawaiian Drosophila are a spectacular example of sequential colonization, adaptive radiation, and speciation in the islands with nearly 1,000 estimated species, of which more than 500 have been described to date.

This dissertation gives an overview of the Hawaiian Drosophila system (Chapter 1), new insights into genomes of three recently diverged species of Hawaiian picture-winged Drosophila (Chapter 2), as well as estimated gene flow patterns (Chapter 3). Additionally, I present a new approach of mapping genomic scaffolds onto chromosomes, based on NextGen sequencing from chromosomal microdissections (Chapter 4), and gene expression profiles of backcross hybrids and their parental forms (Chapter 5). Overall, obtained results were used to address such fundamental questions as the role of adaptive changes, founder effects (small effective population size in isolation), and genetic admixture during speciation.