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VISUALIZING CHANGES IN THE GENOMIC ORGANIZATION OF RETROTRANSPOSONS IN HELIANTHUS HYBRID SPECIES

by Staton, Spencer Evan

Abstract (Summary)
A specific class of mobile DNA called Class I transposable elements, or retrotransposons, occupy a large fraction of the genomic DNA in the flowering plants (the Angiosperms). Given that there has been a 5.6 to 23.6-fold increase in copy number of Ty3/gypsy retrotransposons in the genomes of two hybrid sunflower species (Helianthus deserticola, H. paradoxus), I investigated whether these elements have invaded new regions of the hybrid genomes, relative to the parents (H. annuus, H. petiolaris). I use Fluorscence in situ Hybridization (FISH) to compare the genomic organization of these elements in the parents and hybrid species. Here I show a significant expansion of Ty3/gypsy retroelements around the centromeres of two hybrid sunflower species and that retrotransposons are dispersed throughout sunflower genomes. This observation is consistent with the idea that plant genomes accommodate large additions of DNA in primarily heterochromatic regions, and that large plant genomes contain many dispersed retroelements.
Bibliographical Information:

Advisor:

School:Miami University

School Location:USA - Ohio

Source Type:Master's Thesis

Keywords:helianthus hybrid speices fish retrotransposons genome expansion pericentromere

ISBN:

Date of Publication:01/01/2008

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