The Barcode of Life - Interview Prof. Pedro CrousThe idea of barcoding is familiar to many: in almost every supermarket the checkout operator shows the ticket labelled with a series of black bars to a laser scanner which responds with a beep; a computer analyses the code, identifies the product and the price is sent to the till.
Now, in an ambitious initiative scientists want to apply this concept to life by using DNA - nature’s unique barcode of every species of animal, plant and microbe - to create a vast library of every living organism on the planet. Such a global DNA barcode database would prove invaluable in numerous ways, from identifying new species of organism and monitoring biodiversity to detecting fraud.
The ECBoL initiative aims to establish a Network of European Leading Laboratories (NELL) among major biodiversity resource centres of Europe. This network will have the capacity to generate DNA barcodes of species at an industrial scale, for identifying life on earth. Once established, the consortium has a goal to initially barcode 1M specimens, representing 100K species within 5 years. Further initiatives will be launched to expand the barcode database in an attempt to represent all known and as yet unknown life on Earth.
The ‘barcodes’ in living organisms are short sequences of genetic material that are unique to that organism. In animals, for example, a particular gene sequence in a structure in the cell called the mitochondrion has been shown to be unique to any given species. Similar sequences have been found for plants, and scientists are actively searching for barcode genes in bacteria, fungi and other micro-organisms.
It’s essential that such an initiative is international in scope, and at this year’s EuroBioForum meeting in Strasbourg in September, Professor Pedro Crous will be putting the case for Europe’s involvement in the International Barcode of Life initiative.
“DNA barcoding will allow us to get a better understanding of life and a better appreciation of life,” says Crous, who is director of the CBS Fungal Biodiversity Centre in Utrecht, The Netherlands.
The key advantage of DNA barcoding over traditional taxonomy to identify organisms is the potential for its great speed and accuracy. “Conventionally organisms are identified largely based on aspects such as their size, colour and unique morphological features,” says Crous. “This gives rise to a situation where many species can be identified only by taxonomic experts, who are few and far between. This can make it difficult to identify known species as well as new ones. DNA barcoding would solve all this.”
The concept is simple. A sample of the specimen is processed to produce the barcode. This is then matched against a library of known barcodes and in this way the specimen is identified.
“So if a shipment of exotic animals arrives at the customs point, you can determine very quickly if it contains endangered species or not and apprehend the involved importers,” Crous says. “You can also answer a whole range of complex ecological and biodiversity questions.”
To do this, the barcode database must first be constructed. The International Barcode of Life initiative was proposed by Canadian scientists and is seeking to raise 150 million Canadian dollars (just under 100 million euros) to barcode 500,000 species over the next five years. The logistics will inevitably be complex, so the initiative is proposing a series of central and regional ‘nodes’ to fund and coordinate the activity across the world. Over the years it is hoped that every species – several million – will eventually be barcoded.
“Europe will be a central node, and to qualify for this it is necessary to raise 25 million dollars in Europe,” Crous says. “Europe needs to play a central role in this initiative. We have amazing collections in museums and herbaria that have been gathered over the past centuries – the lion’s share of all the species known on Earth are represented in European collections. We also have a strong tradition of taxonomy, so we are in a uniquely powerful position to make a real impact in this field.”
At the EuroBioForum meeting Crous will put forward proposals for a Network of European Leading Laboratories (NELL) to undertake most of the barcoding work. “At the moment we have eight or nine European countries with co-ordinators committed to this proposal” Crous says. “What we want to achieve at the EuroBioFund meeting is to get commitment from industry and governments that support biodiversity research to commit to this European barcoding campaign.”
As technology develops, barcoding will become increasingly simple and widespread, Crous predicts. “One of the ultimate goals is to develop a hand-held DNA barcoder,” Crous says. “This sounds very futuristic but is not as far-fetched as it might seem. Already people have portable technology for gene sequencing. There are wireless technologies that would be able to send the barcode data to a central database for matching and receive the result. What is still required is miniaturisation of the whole platform – the entire sample preparation. But various groups are working on this.”
A hand-held system would allow people to carry out instant identification of specimens in the field – in a rain forest, for example, or, closer to home, in a hospital where microbiologists need to identify pathogenic organisms. For instance, an increasing numbers of immuno-suppressed patients are developing infections with organisms that were not previously known as pathogens. Fast and reliable identification of novel diseases can save those patients lives.
“Barcoding is the future,” Crous concludes. “It would be a sin if Europe, with its rich collections and its unique expertise in taxonomy, does not play its part.”
Further InformationProf. Pedro Crous
As director of the CBS-KNAW Fungal Biodiversity Centre (CBS) in Utrecht, The Netherlands, Pedro Crous is one of the world’s leading authorities on fungal taxonomy. His interest in the identification and classification of fungi came by a somewhat circuitous route, however. “I come from South Africa and originally trained in forestry,” he says. “However, I pretty soon became intrigued to answer the question about why all the trees were dying – and that took me into plant pathology. I then became interested in fungi that caused the diseases, and that took me into taxonomy, working to identify these organisms.”
The CBS-KNAW Fungal Biodiversity Centre houses the largest collection of living fungi in the world, with some 60,000 living cultures. The centre, which is more than 100 years old, is an institute of the Royal Dutch Academy of Arts and Sciences (KNAW), which has a mission to make scientific information freely available. “So the idea of a DNA barcode database that is universally accessible online fits in well with this philosophy,” Crous says.