Botany without borders: barcoding in focus

This recent meeting, held on the campus of the University of British Columbia, attracted 1200 delegates and a vast array of talks, but was notable for a remarkable showing of talks and posters on DNA barcoding in plants, spread through many sessions. The Canadian Centre for DNA Barcoding defines barcoding as ‘species identification and discovery through the analysis of short, standardized gene regions known as DNA barcodes’. This approach is somewhat controversial in animals ( Rubinoff et al., 2006 ), although it has been shown to be useful and reliable in many metazoan taxa ( Meyer & Paulay 2005 ; Hajibabaei et al., 2007 ), in which the mitochondrial cytochrome oxidase I (COI) gene is used. However, in land plants, COI evolves far too slowly to be useful, and there is no obvious single universal alternative ( Fazekas et al., 2008 ). Genes that work well in one taxon may perform poorly in other taxa. Additionally, some perfectly good plant species, reproductively isolated and morphologically and ecologically distinct, are too young to show much sequence divergence at most loci. Nevertheless, as we saw at this conference, progress has been made towards identifying genes that serve many of the functions of DNA barcodes, at least in some plant taxa.