Experts To Discuss DNA Barcodes And Their Uses

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Main Category: Genetics
Also Included In: Regulatory Affairs / Drug Approvals;  Veterinary;  Biology / Biochemistry

World experts gathered this week to discuss DNA barcodes and their uses, covering a wide range of areas from medicine to agriculture, health to fraud, from smuggling to exploring our planet's prehistoric life.

About 350 experts from 50 countries met for the third International Barcode of Life conference that took place from 9 to 11 November in Mexico City.

DNA barcoding is a new technique that uses a short DNA sequence from the genome of an organism, living or dead, as a molecular way of identifying the species it belongs to. DNA barcode sequences are very short compared to the entire genome and can be obtained quite quickly and cheaply.

The Consortium for the Barcode of Life (CBO) is an international initiative devoted to developing DNA barcoding as a global standard for the identification of biological species.

Through the CBOL initiative, experts are agreeing a standard for DNA barcoding.

The challenge for the initiative is finding an area of DNA that does not vary much down generations, yet varies sufficiently between species to make identification reliable. A number of studies have shown that for higher animals, the variability of the "Folmer region" at the 5' end of the cytochrome c oxidase subunit 1 mitochondrial region (COI) is very low (about 1 to 2 per cent) and even between closely related species it differs by several per cent, making this the ideal region on which to settle as the standard for DNA barcoding.

This section of DNA is 648 nucleotide pairs long for most groups and is surrounded by regions that are reasonably conserved, making it quite easy to isolate and analyze.

In some groups, COI is not an effective barcode region and a different standard region will have to be sought and agreed on. But the idea is that in all cases, DNA barcoding uses a short, standard region that enables cost-effective species identification.

As the standard is being thrashed out and discussed, all manner of professionals are starting to get interested in its application, from medical and agricultural researchers, to police and customs officers.

For instance, using DNA barcoding, palaeontologists hope to be able to sequence ancient plant and animal remains extracted from degraded DNA in northern permafrost cores to reveal Earth's pre-historic life, and how life on Earth responded to global climate change.

And by analyzing the DNA of gut contents, scientists hope to discover secrets of what eats what in the animal world.

One such group is the The International Barcode of Life Project, headquartered in Guelph, Canada, where barcoding was pioneered. They will be telling meeting delegates about their discovery that eight species of bat feed on over 300 types of insect, one of the largest food webs ever found.

Conservationists are now getting very excited about the application of DNA barcoding to help unravel the complexity of the dynamics in the natural world.

Scott Miller, Acting Under Secretary for Science at the Smithsonian Institution and Chair of the Consortium for the Barcode of Life (CBOL), who are co-hosting the meeting with the Instituto Biologia, Universidad Nacional Autonoma de Mexico (UNAM), told the press that:

"DNA barcoding is opening a new window into the relations between hunter and prey in the wild and how diets may be changing due to climate change."

He explained that like gut contents, soils contain a mixture of species that are hard to identify using convetional tools. Tiny soil organisms eat each other, they eat roots, and all sorts of animal and plant debris, so:

"Knowing what eats what is important to many studies, including investigations into how much carbon dioxide and other greenhouse gases are being released from soils into the atmosphere," said Miller.

Another area of application would be producing evidence to prosecute smugglers of wild bushmeat and other products made from endangered species: a trade that last year netted 15 billion dollars worldwide.

When smoked or sundried, only DNA barcoding can differentiate bushmeat from domestic animal meat like beef, goat or pork, so law enforcement agencies are becoming increasingly interested in the DNA barcode library of endangered species that Dr George Amato of the American Museum of Natural History in New York is compiling.

The hope is that the Mexico meeting will bring about a global agreement on how to do the same with plants, which would for instance help to track down illegal timber trading and regulate herbal medicines, among others.


Biodiversity scientists are using DNA technology to unravel mysteries, much like detectives use it to solve crimes. It is having a profound impact on our understanding of organisms in nature and how they interact with the environment.

Following increases in the number of puffer fish poisoning cases in the US due to fradulent food labelling, the US Food and Drug Administration (FDA) will be telling delegates about their interest in DNA barcoding and the challenge posed by trying to differentiate among different species in marketed seafood, an increasing proportion of which is now imported, and which is also processed to "a point where traditional morphologic species determination is not possible".

An FDA representative told the press that:

"New methods that allow accurate and rapid species identifications are critical for both food borne illness investigations and for the prevention of deceptive practices, such as those where species are intentionally mislabeled to circumvent import restrictions or for resale as species of higher value."

The FDA will also be presenting a study that showed DNA barcoding reliably distinguished the seedpods of Star Anise ( Illicium verum, a herb used in teas, herbal remedies and cooking) from otherwise identical seedpods of a sister species, Illicium anisatin, considered to contain neurotoxic compounds and therefore a health risk.

The delegates will also hear of a case from Canada, where students nationwide collected fish samples from stores and analyzed the resulting DNA data, revealing significant market "mislabelling" of seafood.

Another case that will be presented will be the successful apprehension of a Brazilian smuggler last year who was caught trying to smuggle parrot eggs which he said were quails' eggs, but DNA barcoding revealed that they were the eggs of several species of parrots and macaws, many of which where either threatened or vulnerable.

A medical application of DNA barcoding will help to identify black flies in Brazil and other South American countries where they spread river blindness disease. So far 70 species of black flies have been barcoded to date, about 20 per cent of the number known to science, and including three previously unrecognized.

Other medical applications include identification of malaria mosquitoes in India, parasite bearing freshwater snails in the Cameroons, nematode parasites in Mexico that attack crops, humans and livestock.

Mexico is one of the countries that is moving ahead quickly in using DNA barcoding. Under the auspices of CONACYT, Mexico's National Council on Science and Technology, they have established a national barcode network (MexBOL) involving 60 researchers from 15 institutions.

Mexico now has a number of new "barcode factories" at institutions in the north, center and south of the country, including CIBNOR (Centro de Investigaciones Biológicas del Noroeste), IBUNAM (Instituto de Biología, UNAM), and ECOSUR (El Colegio de la Frontera Sur).

Meeting co-host Patricia Escalante, chair of the Zoology Department, Institute of Biology, UNAM, said this work in Mexico and elsewhere was very important.

"Barcoding is a tool to identify species faster, more cheaply, and more precisely than traditional methods," she explained.

MexBOL will produce barcodes for all important taxonomic groups including national campaigns, such as barcoding all trees (ArBOL), fungi, bees, aquatic insects, crayfishes, fishes, birds, mammals and more.

Escalante explained that:

"We need an accurate inventory of global biodiversity to recognize parasites of medical, economic or ecological importance."

"This work will help develop biological control measures, monitor and control of human diseases and potential zoonoses, manage agricultural and aquaculture pathogens, and detect the presence of invasive species," she added.

The largest barcode factory in the world is at the Biodiversity Institute of Ontario at the University of Guelph in Canada, where DNA barcoding was first proposed and developed.

Similar facilities are being set up at the French Museum National d'Histoire Naturelle, as well as in the Netherlands and Poland.