Australasian Science: Australia's authority on science since 1938

Cryptic Clues: Spot the Difference with DNA

By Angela Lush

Scientists at the South Australian Museum are using molecular techniques to unlock one of nature's secrets – cryptic species.

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Cryptic species appear almost identical and you can't reliably tell them apart based on their physical features. Despite their similar looks, cryptic species are genetically very different and can't interbreed.

In recent years, large-scale DNA sequencing technology has become more efficient and affordable and is increasingly being used to more accurately identify species. The technology is a valuable tool that is enabling researchers to reclassify many of the world's species, more reliably identify existing species, and uncover many new ones.

A study of Australian freshwater crustaceans (amphipods) by Dr Remko Leijs and Dr Rachael King has confirmed the existence of two species using DNA analyses. The two species had previously been classified based on slight physical differences and poorly understood geographical distributions. This made identifications quite haphazard and controversial.

"Identification of the two most common amphipods has been difficult and unreliable. While we thought there may be two separate species, we couldn't be sure," said Dr Leijs.

Dr King, a specialist in crustacean systematics, said that DNA analysis helped make identification based on physical characteristics (morphology) more accurate.

"The DNA analyses have helped us understand more about the group's morphology. They gave us strong clues to the physical...

The full text of this article can be purchased from Informit.

South Australian Museum