Whitehead Lab Overview

Broadly speaking, activities in the Whitehead lab revolve around Evolutionary and Ecological Genomics research.  This line of research seeks to understand how genomes integrate cues from, respond to, and are shaped by the external environment.  We examine genomic responses to stress that occur over physiological timescales (acclimation responses) and over evolutionary timescales (adaptive responses).  Many complementary approaches are integrated into our program, including genome expression profiling using microarrays, population genetics and phylogenetics, and physiology, to study how individuals and species respond to and adapt to environmental stress.  Stressors of interest include those that are natural (temperature, salinity) or of human origin (pollutants). 

Genomics of Physiological Plasticity

Populations and species differ in their tolerance to stress.  Some species can change their phenotype to compensate for broad changes in environmental conditions, whereas other species have narrow tolerance ranges.  Genomic regulatory mechanisms are likely to underpin this physiological plasticity.  A major question in our lab is “what are the genomic bases of differences in physiological plasticity among taxa?”

Killifish as models for Evolutionary and Ecological Genomics

Our current model organisms include killifish of the genus Fundulus.  Why do we study Evolutionary and Ecological Genomics using killifish?  Fish are naturally exposed to a wide variety of environmental stressors by nature of their immersion in aquatic habitats.  Killifish of the genus Fundulus are typified by high physiological resilience.  That is, they are physiologically plastic and capable of adjusting their phenotype to cope with environmental stress, yet species vary in their tolerance ranges.  Different species occupy diverse habitats, and some of these habitats are more “stressful” or more variable than others.  Populations and species of Fundulus have evolved tolerances to different environmental extremes, and therefore provide a wonderful comparative system in which to study the genomic basis of resilience or sensitivity to stress. 

In addition to providing an excellent comparative system for ecological and evolutionary studies, a well-resourced genomics toolkit has been developed for Fundulus making them a particularly suitable organism for environmental genomics.  Dr. Whitehead is a founding member of the Fundulus Genomics Consortium and has contributed to the development and application of cDNA microarrays.  Production of an ~8000 gene array is complete, fully sequenced, well-annotated, and supported by robust bioinformatics in a publicly available searchable database.  Much of this important tool development has been accomplished in the laboratories of Dr. Douglas Crawford and Dr. Margie Oleksiak at the University of Miami.  Our consortium is also currently proposing to have the Fundulus genome sequenced.

In summary, Fundulus is an excellent system for environmental genomics research because they represent the rare combination of a genome-enabled species that is outbred, exhibits extensive genetic, functional genomic, and physiological variation among individuals, populations, and species, exploits diverse ecological niches and has a rich history of evolutionary research.