Polyploidy: Genetics, Evolution and Ecology
Zhang, Peter , Liu, Shao-Lun , Adams, Keith .
Evolution of expression and alternative splicing patterns in gene pairs duplicated by paleopolyploidy.
Multiple ancient polyploidy events (paleopolyploidy) have occurred during the evolution of angiosperms in different lineages. Once of those occurred during the evolution of the Brassicaceae after divergence from the Cleomeaceae, approximately 35 mya. Descendent species have subsequently become diploids. After genome duplication the duplicated gene pairs (homoeologs) can diverge in expression by one or both copies gaining a new expression pattern as a consequence of neofunctionalization or subfunctionalization. Here we have examined the extent of subfunctionalization in about 2500 homoeologous gene pairs in Arabidopsis thaliana. Many cases of potential subfunctionalization were identified by analysis of microarray data and RT-PCR experiments. We also have examined the evolution of alternative splicing after whole genome duplication. We have studied alternative splicing patterns in eight organ types of 50 homoeologous gene pairs. Most of the gene pairs showed differences in alternative splicing patterns. These differences include presence/absence of particular splicing events or distinct organ specificity. Alternative splicing patterns in response to abiotic stress conditions also have diverged between homoeologs. In addition we examined alternative splicing patterns in several sets of tandemly duplicated genes. Alternative splicing was conserved in about 20% of the gene pairs, which was higher than in the homoeolog comparisons. Changes in alternative splicing patterns in duplicated genes may contribute to functional or regulatory divergence. Our results indicate that alternative splicing patterns in duplicated genes evolve rapidly on an evolutionary time scale and have implications for cross-family comparisons of the evolutionary conservation of alternative splicing.
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1 - University of British Columbia, Botanical Garden, Centre for Plant Research, and Botany Department, 6270 University Blvd, Vancouver, BC, V6T1Z4, Canada
Presentation Type: Symposium or Colloquium Presentation
Location: Room 2/Woodward
Date: Tuesday, July 29th, 2008
Time: 3:30 PM