From Gels to Genomics: The Evolving Landscape of Pteridology. A Celebration of Gerald Gastony's Contributions to Fern Evolutionary Biology
Wolf, Paul G. , Duffy, Aaron M. , Roper, Jessie M. .
Inversions in fern chloroplast genomes: the good, the bad, and the tricky.
Resolution of deep phylogenetic branches requires the use of robust markers that are less susceptible to homoplasy than nucleotide sequence data. Gene order data, which describe genome structure, may be a group of such markers. It has been proposed that genome inversion events, resulting in a rearranged gene order, are perhaps less susceptible to homoplasy than the simpler four-state nucleotide sequences. However, the validity of this claim is largely untested. The leptosporangiate ferns present an opportunity to investigate the nature of inversion events because we have what we believe to be a well-resolved phylogeny (although with some deeper branches still unresolved) and variation in gene order indicating multiple genome rearrangements. For example, the inverted repeat of the chloroplast genome of some polypod ferns is reorganized relative to that of Angiopteris (representing a basal fern lineage) and other vascular plants. We used a combination of long PCR and DNA sequencing to map several fern chloroplast genomes. Some of the rearragements in the region of the inverted repeat appear to be composed of separate, definable inversions that occurred at intervals on different phylogenetic branches. However, other rearrangements within the large single copy region clustered on single branches. Thus, some regions appear to have undergone destabilization resulting in a burst of rearrangements. These would only be phylogenetically useful if they occurred on a previously unresolved branch. Other regions underwent sporadic inversions and therefore provide multiple markers.
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1 - Utah State University, Department of Biology, College of Science, 5305 Old Main Hill, Logan, Utah, 84322, USA
2 - Utah State University, Biology, Logan, UT, 84332-5305
3 - Utah State University, Biology, Logan, UT, 84322-5305
Presentation Type: Symposium or Colloquium Presentation
Location: Room 5/Woodward
Date: Tuesday, July 29th, 2008
Time: 10:00 AM