While evolutionary approaches underlie most of the research programs in the Department of Ecology and Evolutionary Biology (EEB), Evolutionary Genetics represents a major focal area in evolutionary studies in EEB.

The Evolutionary Genetics group at Brown consists of five laboratories:

• David Rand
• Annie Schmitt
• Marc Tatar

Collectively these lab groups have 10 postdoctoral fellows, 10 graduate students and five research assistants. The underlying theme of these research programs is the use of genetic and genomic approaches to the study of ecological and evolutionary questions. The research covers a wide range of topics spanning microbial diversity to population genetics to the mechanisms of aging. Likewise, a wide range of methods are employed, including computational and theoretical modeling, DNA sequence surveys, fitness experiments in the lab and field, and mutant analyses in model organisms. This diversity of interests is brought together each Wednesday afternoon in a group meeting known as WEEDS (Wednesday Ecology and Evolution Discussion Session). Graduate students, postdocs and faculty alike present emerging ideas, data sets, grant proposals, etc. for general discussion and dissection.

Research foci include:

Neutrality tests comparing polymorphism and divergence

Molecular population genetics and evolution

The nature of evolutionary forces acting on genes and genomes can be inferred through analyses of polymorphism and divergence in DNA sequences. These studies include more empirical approaches to selection on Drosophila nuclear and mitochondrial genomes (Rand).

Evolutionary Ecology
 

Drosophila insulin receptor (InR) mutants have extended longevity. (Click to enlarge)

What is the best allocation of resources during ones lifetime? Should organisms live fast and die young, or suppress reproduction for greater longevity? Research in this area is addressed using model genomic organisms in both the field and the lab. How Arabidopsis populations have adapted climatic factors governing flowering time is a major focus of the Schmitt laboratory. The genetics and evolution of aging is a primary focus of the Tatar lab, where Drosophila is used to dissect the genetics, endocrinology, ecology and evolution of senescence.
 
 

Arabidopsis genotypes in the field

Ecological and Quantitative Genetics

Most of the laboratory groups working in evolutionary genetics take quantitative- and ecological-genetic approaches to address evolutionary questions. Notably, transplant experiments of defined Arabidopsis genotypes are being used to dissect genotype x environment interactions for a variety of traits. And changes in molecular marker frequencies before and after selection in the wild are being employed to estimate selection on specific loci in barnacles. Both QTL mapping and quantitative complementation analyses of wild and mutant alleles are being used in both Arabidopsis and Drosophila projects to asses the functional significance of natural variation at specific loci affecting flowering time, aging, and enzyme activities.

Different strains of bacteria cultured from a salt marsh in Narragansett Bay

One of the most poorly understood problems in biodiversity is the staggering number of “species” of microbes living just about everywhere on the planet. Surveys of 16S ribosomal RNA diversity are being employed in the Hughes lab and at the Josephine Bay Paul Center at the Marine Biological Labs at Woods Hole, MA to examine questions of specie area curves and evolution in extreme environments.

Several faculty at the Josephine Bay Paul Center add to the strength in Evolutionary Genetics:

Research in these labs involve molecular evolution and genomics of microbial eukaryotes, including the Giardia genome project.

top