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Abstract Detail


Systematics Section/ASPT

Rothacker, Erik [1], Lehman, Jeffery  [1], Conard, Cameron  [2].

Utility of Large Inverted Repeat B primerson the amplification and the measurement of rates of evolution in chlorophyllous and achlorophyllous orchids.

Chloroplast loci are routinely used to determine the phylogenetic relationships of plants. Many loci in this genome function in photosynthesis and are evolutionarily conserved therefore mutations in the chloroplast genome can result in a loss of function. Orchids are parasitic on fungi for at least some portion of their life histories. The tribes of the basal Epidendroideae are mixotriophic with many becoming achlorophyllous and holoparasitic. Previous studies have pointed out that achlorophyllous plants in general exhibit higher TI/TV mutations and are therefore evolving at higher rates then photosynthetic sister taxa. When plants loose chlorophyll, functional constraints on the chloroplast genome are relaxed and should therefore exhibit increased mutation rates. The results can be that primer-binding sites for chloroplast loci may be lost. Numerous previous attempts to amplify chloroplast genes in these orchids using traditional primer sets have failed and there is a need for new primers. The objective of this research is to amplify, assess the phylogenetic utility of the Large Inverted Repeat B region and determine rates of chloroplast evolution in achlorophyllous orchid species and whether achlorophyllous taxa exhibit greater variability than chlorophyllous orchids. Taxa sampled from different genera, representing tribes ofthe basal Epidendroideae were amplified with primers designed for the IRB and sequenced. Analysis indicates that achlorophyllous orchids do possess these loci and that they contain phylogenetic signal and exhibit size variation when compared to green relatives.

Broader Impacts:


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1 - Otterbein University, Department of Biology and Earth Science, 1 South Grove St. , Westerville , OH, 43081, USA
2 - Otterbein University, Department of Biology and Earth Science, 1 South Grove St., Westerville , OH, 43081, USA

Keywords:
Orchidaceae
Phylogenetics
achlorophylly
chloroplast loci.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM
Number: PSY036
Abstract ID:459


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