Genome-wide analyses of variation will be carried out to identify how variation in floral scent influences the population genetic structure and evolutionary histories of plants and associated organisms. Intensive sampling using a genome-sequencing and re-sequencing approach will be used to identify specific, causative genomic regions as opposed to neutral variation associated with historic and contemporary gene flow.
Comparisons among hawkmoth and bee-pollinated species provide an explicit measure of the consequences of pollinator foraging behavior on gene (pollen) flow and can provide insight into mechanisms that facilitate or retard diversification. Due to distinct differences in pollinator foraging behavior and distance, we expect more near-neighbor matings and high levels of gene flow and low genetic differentiation in species primarily pollinated by hawkmoths and the opposite in species pollinatedprimarily by bees. Fitness reductions from intense herbivory by moth species (Hyles or Mompha caterpillars) could result in divergent selection for linalool production. This could lead to fewer visits by hawkmoths and therefore greater reliance on bee pollination.
In order to address the genetic/genomic context of functional traits, linalool in particular, we will collect genomic data using three complementary strategies: Genotyping by sequencing(GBS), genome-wide association studies (GWAS, informed here by high quality, draft genome sequences), and measurement of relative expression (i.e. transcriptome sequencing, or RNA-Seq).