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Dawn Simon


Department of Biological Sciences
University of Calgary

Steven Zimmerly's lab home page

E-mail: dsimon@ucalgary.edu

 
Research Interests:

  I am interested in the origin and evolution of introns. In particular, my research is focused on spliceosomal and group I introns. Despite their apparently distinct evolutionary histories, group I and spliceosomal introns may originate through analogous processes. This hypothesis is based on the observation that splicing is like any other chemical reaction, it can proceed in both forward and reverse directions. "Reverse-splicing" (RS) would result in intron insertion at the RNA level, thereafter, reverse transcription of RNA into DNA, and homologous recombination of the intron-containing DNA would result in intron lateral transfer.  
  My major research interest is concerned with uncovering some of the "rules" that govern where spliceosomal and group I introns are found. Due to the large number of both group I and spliceosomal introns, my study system for this project is rRNA of lichen fungi. We believe there are two major constraints on intron locale in this system. First, the introns must be in an accessible region of the rRNA. This is necessary for both forward and reverse splicing of the introns. This is being statistically tested using secondary and tertiary structures of both the small and large subunits of the ribosome. The second major constraint appears to be flanking sequences. For group I introns this has been well established, but remains controversial for spliceosomal introns. This work will be extended from one gene (rRNA) to entire genomes.  
  A second project is being done in collaboration with David Fewer and Prof. Thomas Friedl at the University of Goettingen, Germany. This project is examining the long-term evolution of a single ancient intron, found interrupting the tRNA Leu gene in cyanobacteria and plastids.  
 


Education:

University of Iowa – B.S. with honors in Biology (1996)

Previous Labs:

University of Iowa – Lab of Dr. Andy Wang		  
  Honors Undergraduate Research: 8/94-8/96  
  Molecular genetics of Chlamydomonas reinhardtii photosynthetic mutants.  

University of Delaware College of Marine Sciences – Lab of Dr. George W. Luther III		  
  REU Intern: 6/95-8/95  
  Chemical/Biological Oceanography of the facultative anaerobe Shewenella putrefaciens.  

Publications:

Haugen, P., D. Simon, and D. Bhattacharya. 2005. The natural history of group I introns. Trends Genet. 21:111-119.

Simon, D., J. Moline, G. Helms, T. Friedl, and D. Bhattacharya. 2005. Divergent histories of lichen rDNA group I introns. J. Mol. Evol. 60:434-446.

Simon, D., Hummel C.L., Sheeley S.L., and D. Bhattacharya. 2005. Ribosomal DNA heterogeneity in the lichens Physcia aipolia and Physcia stellaris. Curr. Genet. 47:389-399.

Simon, D., D. Fewer, T. Friedl and D. Bhattacharya. 2003. Phylogeny and self-splicing ability of the plastid tRNA-Leu group I Intron. J. Mol. Evol. 57:710-720.

Bhattacharya, D., D. Simon, J. Huang, J.J. Cannone, and R.R Gutell. 2003. The exon context and distribution of Euascomycetes rRNA spliceosomal introns. BMC Evol. Biol. 3:7.Full text article (biomedcentral.com)

Bhattacharya, D., F. Lutzoni, V. Reeb, D. Simon, F. Fernandez. 2000. Widespread occurrence of spliceosomal introns in the rDNA genes of ascomycetes. Mol. Biol. Evol. 17:1971-1984.

Dollhopf, M.E., K.H.Nealson, D.M.Simon, and G.W.Luther III. 2000.
Kinetics of Fe(III) and Mn(IV) reduction by the Black Sea strain of
Shewanella putrefaciens using in situ solid state voltammetric Au/Hg
electrodes. Marine Chemistry 70:171-180.

Presentations:

Simon D., D. Fewer, T. Friedl, D. Bhattacharya. Evolution and Self-splicing ability of the tRNA-Leu Group I Intron; presented at the meeting of the Botanical Society of America; Madison, WI August 2002, (oral presentation).		    

Simon D., F. Lutzoni, T. Friedl, D. Bhattacharya. Understanding Group I Intron Lateral Transfer; presented at the joint meeting of the Society for the Study of Evolution, Society for Systematic Biology and American Society of Naturalists; Bloomington, IN June 2000, (poster presentation). 		   

Simon D., T. Friedl, D. Bhattacharya. Lateral Transfer of the 1512 Group I Intron in Lichen-forming Algae; presented at XVII International Botanical Congress; St. Louis, MO August 1999, (poster presentation).		    

Brendel P., G. Luther, B. Lewis, A. Farrenkopf, J. Stecher, S. Theberge, D. Simon, and M. Dollhopf. Development of solid state microelectrodes for the voltametric determination of O(-2), S(-2), Fe, Mn, and I(-1) in marine applications; presented at the AGU/ASLO Ocean Sciences Meeting 12 Feb 1996, (poster presentation).