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Integrating taxonomy

By: Brendan Atkins, Category: Science, Date: 18 Mar 2010

Entomologist Dr Andrew Mitchell is looking to combine morphological and genetic approaches to taxonomy.

Dr Andrew Mitchell

Melanie Pannack © Melanie Pannack

Entomologist Dr Andrew Mitchell joined the Australian Museum in February 2010 after five years with the NSW Department of Agriculture (now part of Industry & Investment NSW).

Andrew trained in classical taxonomic techniques but soon began working with molecular data too.

‘I am particularly interested in the evolution of noctuid moths – an enormous group of about 60,000 species including many agricultural pests as well as the familiar Bogong Moth, Agrotis infusa’, he said.

Andrew’s recent research has rewritten the Noctuidae family tree, splitting the group into five smaller families, leaving only the pest-rich groups such as armyworms, cutworms, bollworms and their kin as true noctuids.

He said that while such studies help to shape our understanding of evolutionary history, they leave many fundamental questions unanswered.

‘What species is this? What do its immature stages look like? Is it the same as the similar-looking species found elsewhere? We often don’t know the answers because the group is overwhelmingly large and the number of taxonomists in Australia is declining.’

These are also the questions that are likely to be of immediate practical application, whether it be in ecology, conservation or pest management.

‘This is where molecular data comes into its own’, he said. ‘At the Museum I have the opportunity to integrate molecular data, such as DNA barcodes, with morphological data.’

DNA barcoding (think forensic DNA fingerprinting for all animals and plants) is an emerging subdiscipline of systematics that holds great promise as a tool both for discovering new species and for automating the routine identification of animal and plant samples.

‘DNA barcoding works by comparing the genetic code from a sample with a vast databank containing the codes of many other known species’, he said.

‘While the possible applications of this technique are vast, it’s no silver bullet, and naive use of DNA barcodes can be misleading. The accuracy of barcode identification depends heavily on the taxonomic expertise used to build the reference database and a thorough understanding of molecular evolution’, he said.

Nevertheless, Andrew is excited by the power and potential of DNA barcoding.

‘In the same way that genomics opened up whole new avenues of medical research that were unimaginable even a decade ago, DNA barcoding presents new challenges and opportunities for biodiversity science.

‘One immediate challenge is to integrate traditional morphological data with the rapidly accumulating DNA sequence data to produce more rapid and robust identification tools’, he said.

‘And what better place to do that than in Australia’s first museum?’