| Abstract Detail
Molecular Ecology and Evolution Staton, S. Evan [1], Moore, Richard C. [1]. Visualizing genomic changes in retrotransposon organization in Helianthus and hybrid species. In the Southwest United States there are three natural homoploid hybrid sunflower species (H. anomalus, H. paradoxus, H. deserticola) that have arisen from the annual sunflowers Helianthus annuus and Helianthus petiolaris. Each of the hybrids inhabits ecologically divergent habitats and exhibits transgressive phenotypes relative to their progenitors. These hybrids also differ from the parents in terms of genome size and content. This genome flux has been accomplished, in part, by the proliferation of specific classes of mobile genetic elements called class I long terminal repeat (LTR) retrotransposons. The specific question that this project will address is; have these retroelements invaded new regions of the hybrid species genomes relative to the spatial distribution of the elements in the genomes of the progenitors? This will be accomplished by physically hybridizing retroelement DNA sequences on the chromosomes of hybrid and parental species and visualizing the spatial distribution of the elements with fluorescence in situ hybridization (FISH). A comparative analysis of retroelement signal in Helianthus will reveal if the organization in the hybrids is divergent or if there is genomic constraint, with respect to the parental patterns. If the organization of elements has not changed significantly, I will conclude that there is a genomic constraint on spatial organization and negative selection associated with insertion into new genomic regions. If I observe that the organization of retroelements has changed significantly in the hybrid species’ genomes, I will conclude that the proliferation of retrotransposons was concomitant with expansion into new regions of the hybrid genomes. Transposable elements are thought to play an active and on-going role in shaping genomes, and the proliferation of retroelements in hybrid sunflowers may suggest an important step in understanding the phenotypic and ecological divergence observed with these species.
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1 - Miami University, Botany Department, 316 Pearson Hall, Oxford, Ohio, 45056, USA
Keywords:
none specified
Presentation Type: Poster:Posters for Topics
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P74011
Abstract ID:1607 |
