My research interests are in evolutionary biology and the genetics of adaptation. Field studies and analytical methods from a variety of different disciplines including genetics, physiology, protein chemistry, and wildlife population biology are being used to address questions about the process of adaptation and natural selection, at both the molecular level and in whole organisms. Waterfowl and other species inhabiting high-altitude regions such as the Andes are of particular interest.

High-altitude regions are characterized by simple physiographic differences in environmental variables such as ambient pressure and temperature that vary across elevational gradients in well-defined ways. This makes the study of natural selection and its effects on genetic polymorphism simpler and less complicated than it might be for complex traits that have many environmental correlates. Hypoxia in particular is one of the most important factors influencing survival at high elevations, and biochemical changes in the blood protein hemoglobin (Hb) have been shown to mitigate the effects of chronic hypoxia in high-altitude adapted populations. Surveys of hemoglobin amino acid polymorphism in Andean waterfowl suggest that genotypic variants that are over-represented in high-altitude populations have different fitness rankings in different elevational zones and influence Hb-O2 affinity. Our studies have further revealed that parallel substitutions evolved in distantly related lineages and are concentrated in the same few regions of the protein. Experimental studies of Hb function and blood properties are being combined with mutli-locus population genetic analyses to study the mechanistic basis of these apparent adaptations. One question we aim to answer is whether the same or different mechanisms underlie parallel changes in replicate lineages that independently colonized the Andes and other high-altitude regions. Other questions focus on the role of phenotypic plasticity, and specifically how individuals modulate their Hb-O2 carrying capacity when they disperse across elevational gradients. Additional projects in our lab are examining the influence of selection on non-coding DNA sequences, as well as a variety of population-level studies of waterfowl species, including their role as intercontinental vectors of avian influenza and paramyxoviruses.

Collaborators include Jay Storz at the University of Nebraska, Roy Weber at the University of Aarhus, Jeff Peters at Wright State University, Mary Kuhner at the University of Washington, and Daniel Cadena and his students at Universidad de los Andes in Colombia. We also maintain close working ties with investigators at the Alaska Science Center and several South American museums including the Centro de Ornitologia y Biodiversidad (CORBIDI) and the Museo Argentino de Ciencias Naturales (MACN).

Students with strong interests in population genetics, high-altitude physiology, Andean biogeography, or any aspect of waterfowl ecology and management are encouraged to contact us.

If you are interested in conducting research in my lab, click here for my suggestions for prospective graduate students. The Department of Biology and Wildlife at the University of Alaska Fairbanks offers competitive teaching and research assistantships. Applications are reviewed twice annually with deadlines on 15 September and 15 January. You can follow recent activitites in my lab on our Google+ website.

Grant support: NSF 0444748, 0746365, 0814322, 0949439/0949931