Evolution and Ecology
Developed a species ID system called 'DNA barcoding', which uses a small DNA fragment to discriminate species.
Imagine hiking through the forest on a gloriously sunny day – the sky is clear, the views are spectacular, and you’re in a vibrant mood. Until, that is, you discover a tick on your thigh, swollen after having feasted on your blood. Did you just contract Lyme Disease? If you happen to have a microscope, a tick identification guide and a good eye – or, perhaps an expert entomologist at hand – you might be able to sort out whether the blood-sucker is a member of a species that carries the disease. But chances are you’re miles from an easy answer, so you start worrying frantically about the tick. And then the mosquito that just bit your arm, the ant crawling up your leg, and the flowers making you sneeze.
If Paul Hebert gets his way, there will be no need to panic. You’ll be able to simply pop the squished bug into a hand-held device, and seconds later learn its species, see a close-up photo and read a full description of its biological traits. The tick was relatively harmless it turns out. The mosquito doesn’t transmit any potential diseases. The flower causes mild hay fever but nothing worse. And the ant is a new species that was previously unknown to biologists. It’s an even better hike than you thought!
Hebert, an evolutionary biologist at the University of Guelph, Ontario, has devoted his career to measuring biodiversity – the variation in life seen in the natural world. The problem is that most of life has never been seen before. To date, scientists have identified around two million species on earth. But they estimate that there are at least ten million, if not more. Hebert’s mission to find and characterize these unknown species has taken him from the tropics of the South Pacific to the fresh waters of the Great Lakes and to the unknown wilderness of the Canadian Arctic. But a nagging problem has always bothered him wherever he went – his toolbox to identify life was holding him back.
In the 1990s, new techniques in molecular biology made DNA sequencing fast and cheap. It dawned on Hebert that he could use these molecular methods to vastly improve and accelerate his efforts. Inspired by the simple barcodes used on food products, he developed a similar approach using DNA. But unlike the black and white lines used in supermarket barcodes, his "DNA barcodes" use nucleotides – the genetic "letters" that make genes. In DNA barcoding, the unique letters in a stretch of each species’ DNA act as a reliable tag to discriminate one species from the next.
Biologists have used DNA to describe species before. But Hebert showed that you could standardize the approach by using the same gene in every animal species. The gene he proposed to use was one called CO1, or cytochrome c oxidase 1. This gene is found in the mitochondria, the energy-producing units of the cell. (Unlike most genes, which are found in the nucleus.) Since mitochondrial DNA acquires mutations faster than nuclear DNA, it differs more between closely related species, making it easy to tell species apart. Hebert showed that the CO1 gene is a reliable species indicator, and his approach is now used around the world. By comparing this gene’s sequence across the animal kingdom, researchers are systematically cataloguing life, and continuously discovering new species along the way.
In 2006, Hebert established the Canadian Centre for DNA Barcoding based at the University of Guelph – the first large-scale facility devoted to DNA barcoding in the world. His efforts have quickly led to a database of barcodes for around 30,000 species. And Hebert has no intentions of slowing down. He plans to have half a million species in his database by 2014 – not a bad pace when you consider that three centuries of scientific research have discovered less than two million species. Several companies are also hard at work developing the hand-held devices he envisions to speed this process up. The devices are reminiscent of the tricorder used in Star Trek to detect alien forms of life. But if Hebert realizes his dream, there might not be alien life to detect, because with every species barcoded, life will no longer be so alien on our planet.