|Evolution of Antarctic fishes
Notothenioidei is a monophyletic lineage that dominates the teleost fish fauna of the Southern Ocean that surrounds Antarctica. The Antarctic notothenioids exhibit several remarkable adaptations to polar conditions including antifreeze glycoproteins and modified physiological performance at cold temperatures. Also, a notothenioid subclade, Channichthyidae or icefishes, are the only vertebrates that lack hemoglobin. The diversification of notothenioids into several pelagic and benthic habitats has provided the basis for their identification as the only adaptive radiation observed among teleosts in marine habitats.
I am interested in developing a species-level phylogeny of notothenioids, and using the phylogeny to estimate divergence times and investigate rates and patterns of diversification in the clade.
My involvement with three expeditions to Antarctica and contributions from other investigators has resulted in a DNA bank that includes 75 of the 124 recognized notothenioid species. I am assembling a multi-gene phylogenetic dataset for the clade that includes data from several nuclear genes.
In addition to our phylogenetic work, my lab is interested in the evolutionary history of hemoglobin loss in the icefishes (Channichthyidae). Collaboration with Bill Detrich and Sandra Parker is focusing on elucidating the role of introgression as the initial step in the loss of hemoglobin, and the population genetics of globin loci in icefishes and closely related dragonfishes (Bathydraconidae).
My work on notothenioids have made important contributions by demonstrating that neutral buoyancy has a single origin in the clade, and buoyancy changes as juveniles grow to adults. My collaborative work with Bill Detrich and Sandra Parker has provided a phylogenetic based reconstruction of the events leading up the loss of hemoglobin in icefishes.