Meeting Abstract
P1.145 Jan. 4 The Evolution of Duplicated Ciliary Phototransduction Pathways OAKLEY, T.H.; WILSON, A.V.*; University of California, Santa Barbara; University of California, Santa Barbara awilson@lifesci.ucsb.edu
The eye is an excellent model for evolution because it is a well characterized complex trait on which there have been extensive studies detailing the biochemistry, physiology and gene interactions involved in its function. One particularly well studied pathway is the phototransduction pathway, a signaling transduction pathway which has a duplicated set of genes in rods and cones. We use the eye here as a system to address the question: How does evolution act at the level of a protein interaction network? Evolutionists view gene duplication evolution as a gene by gene process but, it is possible that this evolutionary process could occur at the level of a gene network or a cell type. We look specifically at proteins involved in the phototransduction pathway of rods and cones. The genes in these pathways have been duplicated, retained and differentially expressed (one paralagous set in rods, one paralagous set in cones) in vertebrate genomes. We have calculated several phylogenies and tested for selection on proteins in the vertebrate phototransduction pathway. Our phylogenetic analyses suggest that rod and cone genes duplicated at or prior to the divergence of jawless fishes and other vertebrates. As we compare these tests across the gene families in the pathway we find evidence to determine whether selection acts as a gene by gene process or on the pathway as a whole. These parallel pathways allow us to investigate the differences in the two pathways and test for selection as a cause for those differences. If selection is found to be the cause of these pathway changing differences, then we can support the hypothesis that selection acts at the level of a cellular pathway. Evolution occuring on a cellular pathway would be interesting for the many genetisists who are now studying protein networks within cells instead of specific protein-protein interactions.
