Christopher S. Willett
Contact Information
Office: 435 Wilson HallEmail: willett4[at]email.unc.edu
Office Phone: (919) 843-8663
Lab Phone: (919) 843-6290
Willett Lab Website
Research Description
At a Glance
- Speciation Genetics: Genetic basis of hybrid breakdown in copepods and the appearance of reproductive isolation via sterility
- Genetic basis of physiological adaptation: Temperature and salinity tolerance in copepods
- Population genetics and molecular sequence evolution
- Conservation genetics: Outbreeding depression, population genetics of threatened species
Synopsis
My research addresses the nature of genetic variation that underlies speciation and adaptation. Specifically, I attempt to unravel how genetic changes at the molecular level can lead to phenotypic changes of evolutionary significance. A major thrust of my research program has been to understand how genetic variation within populations translates into variation between populations and species, and to determine the impact of natural selection on this process. In my current work I am targeting specific genetic systems to determine how they could be involved in generating reproductive isolation through hybrid breakdown. I am also examining the physiological and fitness consequences of variation in these targeted genes. My work has been on two different systems-copepods and moths.
Copepods:
The harpacticoid copepod Tigriopus californicus inhabits rocky, intertidal splash pools in a patchy distribution along the west coast of North America. Populations of this species display dramatic genetic differentiation even between relatively proximate localities. Crosses between these populations typically show hybrid breakdown (decreases in fitness of F2 individuals). Understanding the genetic basis of this hybrid breakdown is a major research project in my lab. The evolution of interactions between mitochondrial and nuclear encoded proteins appears to be one source of deleterious interactions that can contribute to reproductive isolation. We continue to explore this genomic coadaptation in this system along with a number of other candidate genetic pathways. Recent work in the lab has also focused on the nature of adaptation in thermal tolerance among populations of this species and its implications for reproductive isolation in this system.
Moths:
My 
work on moths dealt with the predominate mode of conspecific mate recognition in moths, the sex pheromone system. Specifically I study a protein, the pheromone-binding protein and how it contributes to discrimination by male moths. I have examined the evolution of this protein in a number of different moth families and have uncovered evidence for natural selection acting on this protein in conjunction with changes in the pheromone systems.
