SARAH Z. DUNGAN
If you like whales and evolution, then you've come to the right place! I'm a PhD candidate in the Department of Ecology and Evolutionary Biology at the University of Toronto, supervised by Belinda Chang. My main interest is in understanding the molecular foundations of sensory adaptations that have evolved in cetaceans (whales and dolphins). My dissertation work focuses on the cetacean visual pigments. I combine evolutionary statistics with in vitro protein expression experiments to characterize amino acid substitutions that confer functional adaptations for aquatic vision.
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NEWS
DIM-LIGHT VISION IN WHALES
In cetaceans, rhodopsin is more sensitive in the blue part of the spectrum to maximize visual sensitivity in predominantly blue underwater light. Not only is this blue-shift in sensitivity the result of specific changes to the rhodopsin coding sequence, but these changes also have signatures of positive selection.
Naturally occurring mutations in killer whale rhodopsin inconsistently affect the protein's light-response properties when applied across species, a phenomenon called epistasis. Ancestral differences in the background genetic context of rhodopsin likely influenced its evolution in early cetaceans.