Dipstick technology

Dipstick technology, developed by AIMS researchers, provides a quick and accurate assessment of concentrations of marine species by detecting the DNA they shed into their environments (eDNA).  

Organisms leave a genetic shadow wherever they go.  This technology is a lab-free way of visualising DNA of interest and could have exciting conservation and commercial applications. 

Using the same technology as home pregnancy tests, or the rapid COVID tests, AIMS researchers have measured specific DNA that crown-of-thorns starfish (COTS) release into the seawater.  

COTS are a natural predator of corals and a leading cause of coral loss on the Great Barrier Reef. 

When COTS are in low number they can be difficult to spot using current survey methods. The rapid test can detect very low numbers of the coral-eating pest. It is set to help reef managers more precisely and effectively target COTS outbreaks. 

 

Two small devices have water dropped onto them. The top one reveals 2 vertical lines, the bottom one reveals one line.
A positive and negative dipstick test for crown-of-thorns starfish eDNA

 

Dipstick technology has many other exciting potential applications such as: 

  • detecting invasive species transported in ballast water to ports. Such species can damage fisheries and occlude native species. Early detection allows for early intervention. 

  • more effectively regulating commercial fishing by precisely identifying the species being caught. 

  • monitoring for disease, pests and pathogens in aquaculture including: 

  •  ensuring broodstock coral larvae captured in the wild for research and breeding is healthy and the desired species 

  • ensuring juvenile corals bred in aquaculture, to be deployed onto reefs for restoration purposes, are healthy. 

While dipstick technology and eDNA testing have both been widely used over the past decades, this is the first time they have been combined for use in the field to provide quick results onsite. 

We are working on simplifying and streamlining it to create a kit that can be quickly and effectively used by trained citizen scientists. 

Currently, the test requires filtering a 2-litre water sample through a membrane to capture the eDNA. This eDNA then undergoes PCR amplification which makes many copies of the DNA of interest (like a molecular photocopier). Liquid is then taken from this amplification process and applied to a dipstick which provides a visualisation of the eDNA, even in very low concentrations. 

This research was published in the journal Environmental DNA and supported by a National Geographic Society grant, the Ian Potter Foundation.  

The currently feasibility study is supported by and the partnership between the Australian Government's Reef Trust and the Great Barrier Reef Foundation.

Further information