Research in our lab is rooted in evolutionary ecology, and unified by the goal of understanding how adaptive & non-adaptive evolutionary processes play out in nature. We seek a mechanistic and holistic understanding of these processes by integrating information ranging from genetic sequences to community structure. Members of the lab pursue many different types of projects, including field demography, life history experiments, population and quantitative genetics, experimental ecology, and genomic analyses. Recently, we have begun projects that involve cell culture, functional genetics, epigenetics, and physiological experiments. Despite the ever-expanding array of tools on our lab benches, we remain anchored in the field.
Our conceptual approach is to focus on traits, the features of organisms that set the boundaries of their distributions, mediate their interactions and drive their ultimate success or failure. Focusing on traits allows a mechanistic understanding of the feedback between ecological interactions and evolutionary change. We draw on a variety of disciplines to address fundamental questions about nature and biodiversity: To what extent do adaptive and non-adaptive evolution define the habitats in which a population can persist? How do traits interact, ecologically and evolutionarily, to produce organismal success or failure? How do ecological interactions influence the evolution of gene function, and vice-versa? What are the constraints on adaptation?
Integrating diverse types of information necessitates using a wide variety of techniques, and ours include molecular work (DNA sequencing, microsatellite genotyping, gene expression profiles), field work (observational demography, community structure analyses and in-situ experiments) and laboratory phenotypic assays (life tables, growth rate experiments, and hormone manipulations). We explore new techniques as required by the questions we address, and are currently collaborating to develop cellular and molecular tools such as cell lines, a yeast two-hybrid screen, gene knockdown techniques, and expression localization in Daphnia, our main study organism.
We use Daphnia, a common freshwater crustacean, as our primary model system. Studying Daphnia allows us to juxtapose ecological and genetic data in our explorations of adaptation and divergence as they proceed in the wild because it is uniquely amenable to field work, lab experiments, and genetic and genomic analysis. Daphnia are ecologically important, often being the dominant herbivore in the systems they inhabit, and have been a key study organism since the dawn of experimental ecology. In the lab, they are relatively easy to raise, reproduce asexually, and have generation times under two weeks. And the genetic tools available are expanding rapidly. A number of Daphnia genomes have been sequenced, and a variety of genetic manipulations are possible. Much of this has been facilitated by the Daphnia Genomics Consortium, a group of almost two hundred researchers from around the world. Recently, Daphnia became the thirteenth organism recognized by the National Institutes of Health as a genetic model organism.
Much of our work involves comparisons of populations along the pond-lake gradient, focusing on the divergence of Daphnia into temporary ponds and large permanent lakes. These habitats present very different challenges to Daphnia populations, with major shifts in predators, resources, and the abiotic environment. Most of the traits we study are drawn from thinking about life history evolution and resource exploitation.
Through collaborations with other researchers, we are also involved in projects on Plantago lanceolata, salt-marsh grasses, birds, and Antarctic fish.
Interested in joining us as an undergrad, grad or post-doc?
Some of our amazing ponds and lakes in South Carolina, Wisconsin and Michigan.
Photos of our favorite Daphnia.
Information on clones used by the Daphnia Genomics Consortium
Protocols for Daphnia maintenance and molecular wizardry.