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Comparing short DNA sequences from a standard gene is called DNA barcoding. This technique is being used to help discover, identify and distinguish species.

Why do we need DNA barcodes?

The earth is home to a staggering number of species. Estimates for the number of eukaryote species range from 10 million to 100 million. Traditionally, taxonomy has been used to classify organisms. However, less than 2 million species have been classified since taxonomy began 250 years ago.

In 2003, the idea was proposed that scientists could tell species apart by comparing a short gene sequence from a standard gene. So, could DNA sequencing technology provide a quicker approach for species identification?

Find out more in the article DNA barcoding.

Which gene to sequence?

The first thing scientists had to do was choose a gene to sequence. They wanted one that was common to all living things. It needed to show enough variation to be able to tell species apart, but not so much as to distinguish individuals of the same species.

The 648 base-pair mitochondrial encoded cytochrome c oxidase subunit 1 (CO1) was chosen as the gene.

Find out more in the articles The ideal barcoding gene and More about mitochondria.

Collaborative work

There’s an enormous amount of work involved in determining a barcode for every one of more than 10 million living species on Earth.

Much of this work is being done collaboratively. Two large international initiatives – CBOL and iBOL – have emerged:

  • CBOL (Consortium for the Barcode of Life) – Established in 2004, the consortium promotes DNA barcoding as a new scientific standard. A range of barcoding projects, including ABBI (All Birds Barcoding Initiative), FISH-BOL (the Fish Barcode of Life Campaign) and Bee-BOL (the Bee Barcode of Life Initiative), are part of this consortium.
  • iBOL (International Barcode of Life) – The iBOL project, which began in 2007, aims to analyse 5 million specimens representing 500,000 species over 5 years. Their goal is to assemble a library of DNA barcodes and develop technology that can identify species rapidly and inexpensively.

Species identification is important

Species identification is important in a wide range of scientific and technological fields. These include basic research in taxonomy, evolutionary biology, conservation biology and biodiversity studies, as well as more practical matters such as protecting endangered species, monitoring environmental quality, stopping disease vectors, controlling agricultural pests, identifying birds involved in bird strike and identifying foods.

Read the article Barcoding New Zealand swamp hens to find out more. New Zealand scientists have discovered that Lord Howe Island tree lobsters evolved from different ancestors, this is an example of convergent evolution.

A controversial approach?

…every naturalist knows vaguely what he means when he speaks of a species

Charles Darwin

Despite scientific advances since Darwin’s time, this vagueness still exists. The question at this time is: Will DNA barcoding fulfil its early promise and develop into a ubiquitous, user-friendly tool for species identification?

Find out more on why scientists name species and the modern system for classifying species.

Useful link

In 2009 the first of three volumes offering a comprehensive stocktake of New Zealand’s entire known biological biodiversity – The New Zealand Inventory of Biodiversity – was published by Canterbury University Press.

 

    Published 24 July 2009, Updated 22 May 2012