Evolution of Voltage-Gated Sodium Channel Genes and Other Applications of Phylogeny

Biology Department SeminarDavid Hillis, University of Texas at Austin. Host:Susan AlbertsPhylogenetic analyses are now used throughout biology, and it is hard to pick up a biological journal without seeing phylogenetic trees. Part of this interest in phylogeny stems from the genomics revolution, as phylogeny is necessary to make relevant genomic comparisons. In addition, many human pathogens, especially viruses, evolve so quickly that understanding evolutionary dynamics is a critical part of understanding many human diseases.Phylogenetic comparisons are also important for understanding gene function. Voltage-gated sodium channels evolved in the ancestor of animals, and are critical for the function of nervous and muscular systems that characterize and facilitate animal behavior. Whole-genome duplications resulted in a family of these genes in most vertebrates. These duplications have allowed considerable specialization of function, including electric communication and defense in several groups of fishes, toxic defenses that immobilize or kill potential predators, evolution of venoms that target pain receptors, and the evolution of counter-measures to escape these defenses. Phylogenetic comparisons of sodium channel genes are shedding light onto the function of these genes and the evolution of a wide diversity of animal behaviors.