An extremely exciting development in the use of DNA “bar coding” was brought to my attention this week. (BBC) (Science daily). Two large-scale field studies have apparently showed that different plant species can be distinguished quickly using a gene found in the chloroplast. At the time of the successful early work on bar coding (eg. Hevert et al 2004) it was thought that it would be rather challenging to extend the technique to plants.
Apparently this is not the case. Chloroplast DNA is just as useful as mitochondrial DNA. The new study used the “matK” gene from the chloroplast to identify 1,600 species of orchid from Costa Rica, discovering at the same time that what was previously assumed to be one species of orchid was actually two distinct species that live on different slopes of the mountains. In South Africa the same team was able to use the matK gene to identify the trees and shrubs of the Kruger National Park. In the long run the aim is to create a genetic database of the matK DNA of as many plant species as possible, so that samples can be compared to this database and different species accurately identified.
This could potentially be the most important development in the last fifty years for ecologists and biogeographers. My own institution (Ecosur) is keen to use the technique. If indeed it can be quickly placed in the hands of researchers throughout the tropics, much of the confusion surrounding the distribution and abundance of plants could finally be resolved.
However in order to address some of the most interesting “Wallacean” biogeographic questions (as opposed to “Linnean” taxonomic issues) requires a great deal of investment in new field work (eg Bini et al, Cayuela, Golicher et al en prep). Let us hope that the hard work that will be needed in order to fully research biodiversity “in situ” receives the funding required.
Hebert, P. D. N.; Stoeckle, M. Y.; Zemlak, T. S. & Francis, C. M. (2004): Identification of Birds Through DNA Barcodes. 2(10): 1657-1663.
Bini LM, Diniz-Filho JAF, Ranger TFLVB, Bastos RP, Plaza Pinto M (2006) Challenging Wallacean and Linnean shortfalls: knowledge gradients and conservation planning in a biodiversity hotspot. Divers Distrib 12:475–482