| Abstract Detail
Rodriguez, Christian [1], Smith, Sally J. [1], Miller, Rebecca [2], Oberholzer Vandergon, Virginia [1]. Anthocyanin pathway gene duplication in Hawaiian silverswords and California tarweeds. The silversword alliance represents 28 species endemic to the Hawaiian Islands. Divergence into its many species constitutes an excellent model for adaptive radiation. Though there appears to be a lot of phenotypic variation, studies have shown very little genotypic variation suggesting that a few key loci have contributed to the species differences. One apparent phenotypic difference in this group is pigmentation resulting in white, yellow and red flowers. The relevant pathway for pigment production is the anthocyanin pathway. Chalcone synthase (CHS) is the enzyme of the pathway's first committed step and dihydroflavonol reductase (DFR) is a later gene in the pathway. Focusing on the evolution of these gene families in select species of silverswords may lead to a general understanding of some of the phenotypic changes that occurred in this radiation. Our work has shown that CHS has at least 2 copies and DFR has 3 copies in the genomes of Madia elegans (mainland relative, tarweed) and Dubautia linearis (Hawaiian). The deduced protein sequences contain the signature motifs of CHS and DFR. Comparison of the 2 CHS clones for D. linearis and M. elegans indicate that Dlinearis1 and Melegans1 are more similar to each other than Dlinearis1 is to Dlinearis2 and vice versa. This suggests that the duplication event occurred before the mainland progenitor invaded the islands. Preliminary results also indicate that DFR may have a similar gene history duplicating before the radiation event. Research into the evolution of these and other important genes involved in the anthocyanin pathway may ultimately contribute to the understanding of the history of the Hawaiian silverswords, many of which are endangered or threatened.
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1 - California State University, Northridge, Biology, 18111 Nordhoff St., Northridge, CA, 91330-8303, United States
2 - California State University, Northridge, Biology Dept, 18111 Nordhoff St, Northridge, CA, 91330, USA
Keywords:
anthocyanin
chalcone synthase
Hawaiian silversword
molecular evolution
adaptive radiation
Dihydroflavonol reductase.
Presentation Type: Array
Session: TBA
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: 010
Abstract ID:1186 |
