Systematics/Phytogeography / Taxonomie/ Section
Newmaster, Steve , Fazekas, Aron , Steeves, Royce , Janovec, John .
Testing plant barcoding regions in South American wild nutmeg trees.
The concept and practice of DNA barcoding have been designed as a system to facilitate species identification and recognition. The primary challenge for barcoding plants has been to identify a suitable region on which to focus the effort. The slow relative nucleotide substitution rates of plant mitochondria and the technical issues with the use of nuclear regions have focused attention on several proposed regions in the plastid genome. One of the challenges for barcoding is to discriminate closely related or recently evolved species. The Myristicaceae, or nutmeg family, is an older group within the angiosperms that has evolved slowly at a molecular level and contains some recently evolved species providing a challenging test for barcoding plants. The goal of this study is to determine the relative utility of six coding (Universal Plastid Amplicon — UPA, rpoB, rpoc1, accD, rbcL, matK) and one noncoding (trnH-psbA) chloroplast loci for barcoding in the genus Compsoneura using both single region and multiregion approaches. Five of the regions we tested were predominantly invariant across species (UPA, rpoB, rpoC1, accD, rbcL). Two of the regions (matK and trnH-psbA) had significant variation and show promise for barcoding in nutmegs. We demonstrate that a two-gene approach utilizing a moderately variable region (matK) and a more variable region (trnH-psbA) provides resolution among all the Compsonuera species we sampled including the recently evolved C. sprucei and C. mexicana. Our classification analyses based on nonmetric multidimensional scaling ordination, suggest that the use of two regions results in a decreased range of intraspecific variation relative to the distribution of interspecific divergence with 95% of the samples correctly identified in a sequence identification analysis.
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Molecular Ecology Notes Paper
1 - Univeristy of Guelph, Integrative Biology, 50 Stone Rd East, Guelph, Ontario, N1G 2W1, Canada
2 - Botanical Research Institute of Texas, 509 Pecan Street, Fort Worth, Texas, 76102, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Room 1/Woodward
Date: Monday, July 28th, 2008
Time: 1:30 PM