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Abstract Detail



Systematics Section/ASPT

Bird, Kevin [1], Edger, Pat [2], Tang, Michelle [3], Mayfield-Jones, Dustin [4], Conant, Gavin [5], Mummenhoff, Klaus [6], Koch, Marcus [7], Pires, J. Chris [8].

Assessing the Phylogenetic Utility of the ITS Regions.

The internal transcribed spacers of the nuclear ribosomal RNA gene cluster, termed ITS1 and ITS2, are the most frequently utilized nuclear markers for phylogenetic analyses across many eukaryotic groups including most plant families. The reasons for the popularity of these markers include: 1. Ease of amplification due to high copy number of the gene clusters, 2. Available cost effective methods and highly conserved primers, 3. Rapidly evolving markers (i.e. variable between closely related species), and 4. The assumption (and/or treatment) that these sequences are non-functional, neutrally evolving phylogenetic markers. Here, our analyses of ITS1 and ITS2 for 50 species suggest that both sequences are instead under selective constraints to preserve proper secondary structure, likely to maintain complete self-splicing functions, and thus are not neutrally evolving phylogenetic markers. Our results indicate the majority of sequence sites are co-evolving with other positions to form proper secondary structure, which has implications for phylogenetic inference. We also found that the lowest energy state and total number of possible alternate secondary structures are highly significantly different between ITSregions and random sequences with an identical overall length and Guanine-Cytosine (GC) content variation. Lastly, we review recent evidence highlighting some additional problematic issues with utilizing these regions as phylogenetic markers, and thus strongly recommend alternate markers and cost-effective approaches for future studies to estimate phylogenic relationships.


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1 - University of Missouri, Biological Sciences, 2229 Grindstone Pkwy, Columbia, Missouri, 65201, USA
2 - University of California, Department of Plant and Microbial Biology, Berkeley, CA, 94794, USA
3 - University of Missouri, Biological Sciences, Columbia, MO, 65211, USA
4 - Division Of Biological Sciences, 5228 S 37th Street, Saint Louis, MO, 63116, USA
5 - University of Missouri, Animal Science, Columbia, Missouri, 65211, USA
6 - University of Osnabruck, Biological Sciences, Osnabruck, Germany
7 - Heidelberg University, Department of Biodiversity and Plant Systematics, Centre for Organismal Studies, Heidelberg, Germany
8 - University Of Missouri, 371 Bond Life Sciences Center, 1201 Rollins Street, Columbia, MO, 65211-7310, USA

Keywords:
phylogenetics
Brassicaceae
Internal Tanscribed Spacer
Secondary Structure
ITS phylogeny
Mustards
Arabidopsis thaliana.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PSY053
Abstract ID:130
Candidate for Awards:Genetics Section Poster Award


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