Plant & Animal Genomes XVI Conference

January 12-16, 2008
Town & Country Convention Center
San Diego, CA

Consequences Of Genome Duplication In Teleost Fish.

John H. Postlethwait

  University of Oregon, Institute of Neuroscience, Eugene OR, 97403, USA

Genome duplication events have punctuated the evolution of vertebrate and flowering plant genomes. Two rounds of genome duplication (R1 and R2) likely occurred at the base of the vertebrate radiation and another (R3) at the base of the teleost radiation. After a genome duplication event, most duplicated genes rapidly revert to single copy. Genes retained in duplicate generally come to be expressed in overlapping but distinct patterns in development, a process modeled by subfunction partitioning and the origin of novel functions. Genome duplication preserves the stoichiometry of genes in a regulatory network. Ohnologs (paralogs arising from genome duplication) begin to revert from two copies to single copy after the duplication, but if only a few genes in duplicated networks survive in duplicate, and if ohnologs survive in duplicate because they are at least partially non-redundant, then regulatory links among surviving genes may become more complex than before duplication. How do developmental genetic regulatory networks evolve after genome duplication? Is one set of ohnologs used in one group of cells or developmental processes and the duplicate set in other cells or processes? Or does the pathway evolve in an interrelated array of interacting components much more complex than the original network? When in the teleost radiation did most of the events occur that preserved duplicate genes? If early, then the functions of orthologs in most teleosts will be generally similar, but if later, then the functions of a gene in one teleost might not be a good predictor of its function in another species. As a test system, we investigate gene functions in skeletal development in zebrafish and stickleback, with tetrapod gene function as the unduplicated outgroup, to infer the evolution of regulatory complexity and its relationship to diversity with respect to the teleost genome duplication.