BURCH, M. N.*; MOORE, B.; GUILLETTE, JR., L. J.; BRAUN, E. L.; Department of Zoology, University of Florida, Gainesville, FL 32611; Department of Zoology, University of Florida, Gainesville, FL 32611; Department of Zoology, University of Florida, Gainesville, FL 32611; Department of Zoology, University of Florida, Gainesville, FL 32611: Phylogenomic Analyses of Gene Duplication in Holostean Fish

Genomes change over evolutionary time and one important type of genomic change is gene duplication. Teleost fish possess a larger number of duplicated genes than other vertebrates. The presence of these numerous duplications suggests a complete genome duplication in teleosts. While there is growing evidence for this genome duplication, there has been limited investigation of the evolutionary timing for this putative duplication event. Therefore, we have begun an effort to clone and sequence six genes (cyp19, DLL, ER-&beta, HUR, Notch, and RXRB ) that have been duplicated in teleost fish. The species examined (list) are representatives of the most evolutionarily basal, ray finned fishes. mRNA has been extracted and partial sequences of DLLa, ER-&beta and RXRD have been obtained. Progress has been made with the genes encoding cyp19b, cyp19g, Notch and HUR. Our data for the genes examined to date suggest that these genes are not present as duplicates in holostean fish, although some ambiguous results were evident when different analytical methods were used. Upon completion of the full dataset we will conduct phylogentic analyses of all genes to establish the timing of gene duplications in a manner that will be insensitive to gene loss. Analysis of these results should establish when any genome duplication event occurred.