Dr. W. John Kress and colleagues of the Smithsonian Institution demonstrate the Use of DNA Barcodes to Identify Flowering Plants, a study detailing techniques on plant DNA profiling using methods commonly applied to animal samples. Their work appears in the latest issue of the Proceedings of the National Academy of Sciences.

One method used in DNA profiling is PCR (or polymerase chain reaction) amplification of a short segment of DNA whose copy number, length, or sequence may be different from individual to individual. The cytochrome c oxidase 1 sequence is widely applicable to animal DNA profiling, but cannot be used for plants, since its rate of evolution is much slower.

In the study, researchers demonstrated that the trnH-psbA intergenic spacer, present in plastid DNA, is a potential target for plant DNA profiling, at least for flowering species. Using data from analysis of the plastid genomes of the deadly nightshade (Atropa belladonna) and Nicotiana tabacum, researchers developed specific primers for the spacer sequence, then tested them by conducting PCR on 99 species, from 80 genera, and 53 families of flowering plants. Results showed that use of the spacer could discriminate amongst the species, some of which were museum specimens around 20 years old.

To download the article, go to http://www.pnas.org/cgi/content/full/102/23/8369