Assistant Professor;
Ph.D., University of Oslo, 1997

Research and Professional Interests:

I am a theoretical evolutionary biologist who uses mathematical modeling as my chief research tool. I have background and interests in mathematical and statistical modeling within a wide range of topics including population genetics, population dynamics, and phylogenetic analysis.

My current research is focused at the interface between evolutionary genetics and trait adaptation. Evolutionary theory contains a sophisticated and detailed account of how adaptations are produced and maintained by natural selection, but selection is based on available genetic variation, and the "variational" properties of organisms are less well understood. A major challenge for evolutionary biology is to understand the laws of organismal variation and how they relate to evolutionary change. Some of the questions I ask in my research are: (1) To what extent is the observed genetic variation of a character available to build adaptations, and to what extent is it constrained by conflicting selection pressures and pleiotropic interactions with other characters? (2) What are the properties of new mutations and how do these properties affect adaptation? (3) How do the effects of genes and mutations depend on the genetic background? (4) What is the relation between mutational properties and genetic architecture? (5) How do the variational properties of organisms evolve? (6) What makes a character evolvable and how does evolvability evolve? One approach I take to these questions is to study the evolution of genetic architecture through mathematical modeling. A lot of this work is based on a general model of gene interaction I have developed in collaboration with Günter Wagner and Joachim Hermisson. Through simulation and analytical techniques we use this model to study the evolution of mutational properties and gene effects, as well as the evolution of the genotype-phenotype map itself. A related project uses the model as a statistical tool to estimate aspects of genetic architecture from various types of genetic data.

I also pursue some of these questions empirically. In collaboration with David Houle and Ashley Carter, I study the genetic basis of evolvability in the wings of fruitflies through artificial-selection experiments. Another project, in collaboration with Scott Armbruster, Christophe Pelabon, and Matt Carlson, involves quantitative genetic studies of floral variation in Dalechampia vines. The "blossoms" of these plants are functionally integrated inflorescences that secrete resin from a specialized gland to attract bees that use resins as nest-building materials. We seek to characterize the variability and evolvability of the blossoms and relate these to adaptive diversity among populations and species.

Publications
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