Speciation, in which one ancestral population gives rise to two or more descendant species with distinct characteristics, is the fundamental evolutionary process generating the diversity of life on earth. This project will harness recent advances in DNA sequencing technology to examine in unprecedented detail the ways in which history, geography and natural selection combine to produce the genetic changes responsible for the evolution of new species. This is basic research that aims to advance the new field of speciation genomics and increase fundamental knowledge of the natural world, while testing the hypothesis that natural selection on a small number of genes is sufficient to generate new species. The project will also generate important data for setting conservation priorities, provide advanced training in molecular and computational biology for a graduate student, and create opportunities for engaging students and the general public in modern genomics research with an accessible example involving birds.
This research focuses on twelve finch species (genus Lonchura) that represent one of the most extraordinary cases of recent and rapid diversification in birds. With a diversity of plumage patterns and replicate examples of closely related species living in the same geographic regions, this group is ideally suited for addressing fundamental questions about the genomics of speciation. Whole genome sequencing combined with targeted re-sequencing will be used to characterize patterns of genetic diversity and divergence among species and populations in the Lonchura radiation and to: 1) assess the number, size and location of genomic regions (i.e., genes) diverging early in the speciation process; and 2) test alternative models for the origin and history of genetic variants (i.e., alleles) in these regions. The general hypothesis that each species' phenotype has evolved through the fixation of genetic variants at a small number of genes and that the phylogenetic history of these genes is largely decoupled from genome-wide patterns of genetic variation will be tested. Of particular interest is the possibility that novel genetic variants have been transferred between species via hybridization, resulting in novel phenotypes generated by unique combinations of alleles across a small subset of genomic loci.