Magazine article ROM Magazine

Barcoding Life: Demystifying the Project That Aims to Classify the World's 32 Million Species Using Only a Short Strand of DNA Ten ROM Biologists Report

Magazine article ROM Magazine

Barcoding Life: Demystifying the Project That Aims to Classify the World's 32 Million Species Using Only a Short Strand of DNA Ten ROM Biologists Report

Article excerpt

Introduction

Everyone can identify a cow or a daisy. But there are millions of organisms on earth that only an expert in a highly specialized field of study can pinpoint as a particular species. Now identification is about to get much easier for experts and, eventually, for anyone with an interest in or curiosity about nature. A new method called DNA barcoding is helping biologists to rapidly identify individual species, similar to the way a supermarket barcode quickly identifies a particular product. Championed by Dr. Paul Hebert at the Biodiversity Institute of Ontario at the University of Guelph, genetic barcoding, rather than scanning a series of bars, reads a short segment of DNA.

All life is coded by DNA--a double-stranded helix structure made from four nucleotide bases--adenine (A), thymine (T), cytosine (C), and guanine (G). The sequence in which A, T, C, and G are strung along the strand of DNA in organisms' cells ultimately determines the species.

The barcoding approach is poised to make identification of the earth's almost 2 million known species and discovery of the estimated 30 million species yet unknown a far less daunting task. Being able to quickly identify species has many useful applications. Mosquitoes, for example, transmit diseases such as malaria and West Nile virus.

Having fast and reliable identification helps medical workers to target the correct one of several thousand mosquito species and effectively fight these devastating human health problems throughout the world. Fungi provide another example. Among the yet-to-be-discovered species of this particularly poorly known group of organisms may be new yeasts that would improve food production or lead to new drugs to combat infections. The scientific discipline called taxonomy--the study of categorizing and naming species--aims to classify our world's immense biodiversity. To meet the challenge of discovering and identifying species, resources to support this work and innovations in methodology must be stepped up--before these undiscovered species and their potential benefits are lost without a trace. DNA barcoding is providing taxonomists with a new tool to speed things up. The ROM is one of the first of many institutions, including the Smithsonian, Harvard, and Academy of Natural Sciences in Philadelphia, to partner with the University of Guelph on the International Barcode of Life Initiative, a project that aims to build a reference database of genetic sequences for all species on earth. Since the project started in 2003, about 20 to 30 percent of species in familiar groups such as birds and mammals have been barcoded. Within the next five years, researchers will be able to quickly search this comprehensive catalogue to compare the barcode of a species they wish to identify with those of all species in the database. As of the beginning of 2009, there are already more than 50,000 species of organisms represented by more than 500,000 DNA barcodes of individual specimens. The ROM has contributed tens of thousands of tissue samples from our collections for this purpose.

The seven reports in this special feature summarize the research conducted by the ROM curators who are working at the forefront of molecular biology on this collaborative global project.

What is DNA Barcoding?

A primer on this new field of research

DNA barcoding is a way to identify species using a short sequence of DNA from a standard part of the cell's genome, or genetic material. This system is similar to a supermarket scanner that reads a pattern of lines of different thicknesses, called the Universal Product Code, to identify a specific item for purchase.

Traditionally, biologists identified biological species by looking at specific characteristics of its shape or form--called morphological features. Some organisms don't have obvious differences in their external appearance, such as colour variation or number of appendages, so a taxonomist was needed to analyze the smallest details for clues--things like minute cusp patterns on the teeth or fine structural details of the skull. …

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