Barcodes are used to identify all sorts of things, from bottles of shampoo to hockey pucks to polar bears. Wait a minute—polar bears? Yes, there’s a new kind of “biological barcode” that can identify all animal and plant species on earth based on their unique DNA (deoxyribonucleic acid) sequences.
Scientists at the University of Guelph launched a global project in 2010 called the International Barcode of Life (iBOL)through which they are building a huge database of these DNA barcodes. Knowing which species live in the earth’s various ecosystems is the first step in protecting our planet’s biodiversity.
Did You Know?
Earth is home to as many as 100 million different species of animals, plants, fungi and bacteria, but fewer than two million species have been identified.
What exactly is a DNA barcode? DNA is the “recipe” molecule for all living things. A gene is a segment of DNA that encodes instructions for making a protein. Proteins do the heavy work of building and maintaining an organism. At the molecular level, the components of DNA that form the genetic code are the nitrogenous bases called adenine (A), thymine (T), cytosine (C) and guanine (G). The sequence of A, T, C, and G molecules dictates how proteins are constructed, and this sequence is different between different species. The exact A, T, C, G sequence of a standardized segment of DNA is the unique DNA “barcode” for that species.
How do DNA barcodes help with species identification? Traditionally, species have been identified by characteristics like size, colour and shape. But, this can get tricky when specimens are damaged or incomplete, or when different species look identical. Since DNA is found in nearly all cells and doesn’t degrade easily, it can be isolated from damaged or incomplete specimens. Moreover, two different species will have different DNA barcodes, no matter how much they look alike.
Did You Know?
DNA barcoding was first developed in Canada. University of Guelph scientist Dr. Paul Hebert published the technique in 2003 and he leads the iBOL project.
Why is iBOL important? With so many of earth’s species threatened by climate change and habitat destruction, it is important to have the best census possible of life on our planet. iBOL scientists are collecting DNA barcodes for a wide range of living things including fish, birds, butterflies, ants and flowering plants. DNA barcoding provides an unambiguous way to identify species—and we can only protect a species if we know of its existence.
More information about the International Barcode of Life project
Scientific details about DNA barcoding
Using DNA barcoding to expose fish fraud
Article first published May 11, 2011