Genomics of speciation, reproduction, and conservation

What are the first genes to change during the formation of new species? How do novel reproductive traitsĀ  evolve? We seek to understand the genetic architecture of traits that alter reproduction, to understand what maintains reproductive isolation among populations or leads to loss genetic diversity in threatened or declining species. We want to know how multiple barrier traits become coupled together within the genome, possibly within rearrangements (or supergenes).

Some of our research uses the European corn borer moth (Ostrinia nubilalis) for identifying the genetic basis of reproductive traits. Populations of this sweet corn pest can vary in mating pheromone, male pheromone preference (mapped to the gene bric-a-brac), and the seasonal timing of mating (mapped to period and pigment dispersing factor receptor). Many of these traits are associated with a large rearrangement on the sex chromosome.

Our research studies the genetic divergence and traits related to reproduction among Callophrys elfin butterflies (subgenus Incisalia). We are studying differences in emergence timing in the Eastern pine elfin (Callophrys niphon) and investigating genetic diversity related to host plant differences in the imperiled frosted elfin (C. irus). We are using genomic approaches to study the causes of mito-nuclear discordance in the genus and possible hybridization of brown elfin (C. augustinus) with related elfin species.

Temperature effects on reproduction and epigenetic change in warming climates

Plasticity and learning also play an important role in reproductive trait divergence. If mating traits depend on the environment, shifts in the environment could alter reproductive traits in a way to weaken reproductive isolation. We are studying the effects of elevated temperature and nutritional resources during mating on reproduction in Ostrinia nubilalis. DNA methylation has not been well-studied in most lepidopteran species and we are investigating mechanisms associated with plasticity in reproduction through studies of gene expression and DNA methylation. We are measuring the life-stage specific effects of heat exposure and shifts in DNA methylation profiles in reproducing Ostrinia males and females. In ongoing collaborative work, we are comparing DNA methylation in response to heatwaves in several species of Lepidoptera to determine unique and common epigenetic responses to heatwaves, giving insight into the broader molecular basis of plasticity.

Other collaborative projects in from the lab focus on genetic changes associated with life-history traits in warming climates (adaptation to temperature) and supergene evolution in both invertebrates and vertebrates.

Other past research topics:

Cascade reinforcement– contact between species leading to further changes in mating traits
Chromosomal rearrangements in speciation
Mate choice, predation, and hybridization