Hilu, Khidir W. , Black, Chelsea , Crawley, Sunny S , Oza, Dipan .
Phylogenetic signal, gene tempo and depth of resolution: the rosids.
It has been proposed recently that phylogenetic signal derived from slowly evolving genes is effective in discerning deep evolutionary histories whereas phylogenetic signal from rapidly evolving genes are more useful in resolving shallow evolutionary histories. We contrast here phylogenetic structure (resolution and support) obtained from sequences of two slowly evolving genes (rbcL and atpB) with that recovered from two rapidly evolving genomic regions (matK and trnK intron) in the rosid clade. The rosids contain more than 25% of angiosperm species and is comprised of two major clades (fabids and malvids) plus relatively smaller ones. Resolving the structure of the rosid lineage has been one of the main challenges in angiosperm systematics. As such, the rosids provides a good case study for evaluating mode of gene evolution in relation to depth of phylogenetic resolution. The two sets of genes/genomic region we used are comparable in number of nucleotides, and all are components of the plastid genome. Using maximum parsimony and maximum likelihood methods, the partitioned analyses show that rapidly evolving genomic regions overall provide as much as if not more structure than the slowly evolving ones in the rosids. Resolution and support at deeper nodes range from being comparable to better than that obtained with slowly evolving genes depending on the phylogenetic method. The rapidly evolving genomic regions alone and in combination with the slowly evolving genes provide an improved structure for the rosids across the phylogenetic tree.
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1 - Virginia Tech, Biological Sciences, Blacksburg, Virginia, 24061, USA
2 - Virginia Tech, Biological Sciences, Blacksburg, VA, 24061, USA
3 - Virginia Tech, Biological Sciences, 2119 Derring Hall, Blacksburg, VA, 24061, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Alpine C/Snowbird Center
Date: Monday, July 27th, 2009
Time: 8:00 AM