|
May 31, 2005
Proceedings of the National Academy of Sciences
May 31, 2005
Use of DNA barcodes to identify flowering plants
W. John Kress,
Kenneth J. Wurdack,
Elizabeth A. Zimmer, Lee A. Weigt, and Daniel H. Janzen|
ABSTRACT
Methods for identifying species by
using short orthologous DNA sequences, known as "DNA
barcodes," have been proposed and initiated to
facilitate biodiversity studies, identify juveniles, associate
sexes, and enhance forensic analyses. The cytochrome c
oxidase 1 sequence, which has been found to be widely
applicable in animal barcoding, is not appropriate
for most species of plants because of a much slower
rate of cytochrome c oxidase 1 gene evolution
in higher plants than in animals. We therefore propose
the nuclear internal transcribed spacer region and the
plastid trnH-psbA intergenic spacer as
potentially usable DNA regions for applying barcoding
to flowering plants. The internal transcribed spacer
is the most commonly sequenced locus used in plant phylogenetic
investigations at the species level and shows high levels
of interspecific divergence. The trnH-psbA
spacer, although short ( 450-bp),
is the most variable plastid region in angiosperms
and is easily amplified across a broad range of land plants.
Comparison of the total plastid genomes of tobacco and
deadly nightshade enhanced with trials on widely
divergent angiosperm taxa, including closely related
species in seven plant families and a group of
species sampled from a local flora encompassing 50
plant families (for a total of 99 species, 80 genera, and
53 families), suggest that the sequences in this pair of
loci have the potential to discriminate among the
largest number of plant species for barcoding
purposes.
Source:
www.pnas.org/cgi/doi/10.1073/pnas.0503123102
Freely available online through
the PNAS open access option:
www.pnas.org |
