University of Toronto helps to 'barcode' the world's plants

An international team of scientists, including botanists from the University of Toronto, have identified a pair of genes which can be used to catalogue the world's plants using a technique known as DNA barcoding — a rapid and automated classification method that uses a short genetic marker in an organism's DNA to identify it as belonging to a particular species. "Barcoding provides an efficient means by which we can discover the many undescribed species that exist on earth," says Spencer Barrett, a professor of ecology and evolutionary biology at the University of Toronto and the head of the Canadian plant barcoding working group. "This discovery is important because understanding biodiversity is crucial to long-term human existence on the planet."

DNA barcoding has been widely used to identify animal species since its invention five years ago. But its use for plants was delayed because of the complex nature of plant genetics and disagreements over the appropriate DNA regions to use.

"We compared the performance of the seven leading candidate gene regions against three criteria: ease of obtaining DNA sequences; quality of the DNA sequences; and ability to tell species apart based on a sample of 550 species of land plants", says Barrett. "Based on this global analysis we recommended that matK and rbcL — two chloroplast genes — are adopted as the DNA barcode for land plants."

The primary application of the methodology will be the identification of the many species in the world's biodiversity hotspots where a shortage of specialists hinders conservation efforts. Other applications include identifying illegal trade in endangered species, identifying invasive organisms, poisonous species and fragmentary material in forensic investigations. The technique will work on minute amounts of tissue and can be used on fragments of plant material, small seedlings, and in some cases digested or processed samples.

The methodology will also be used immediately in global projects such as Tree-BOL which aims to build the DNA barcode database for all the species of trees of the world — many of which are of economic and conservation importance.

The report appears this week in Proceedings of the National Academy of Sciences under the group authorship of the Consortium for the Barcode of Life (CBOL) Plant Working Group.

Source: University of Toronto