Science Centres: Aquatic Biodiversity and Biosecurity

Blenny specimen (Rudie Kuiter, Aquatic Photographics)

In crime-fighting TV serials, DNA techniques often crack the impossible case.

Recently NIWA used DNA techniques to identify an invasive blenny found in Auckland.

By comparing the DNA sequences in a range of blenny species from Australia, we were able to show that those in the invasive blenny closely matched those from Omobranchus anolius, but not those from three other species in the same genus. However, minor differences in the DNA sequences indicated that the Auckland specimens were not derived from O. anolius populations in New South Wales, but from some other part of Australia.

How it works

Typically, different species are characterised by a unique base composition in their DNA sequence. A string of just four bases – adenine, cytosine, guanine, and thymine – forms the ‘code of life’ in all animals and plants. Unknown specimens are identified by matching the base composition in a short sequence of their DNA against similar sequences from known species.

DNA can be recovered from small tissue samples, including dried and preserved specimens, allowing the identification of historical specimens and the detection of invasive species in plankton samples taken from ballast water.