An innovative detection tool: Environmental DNA or eDNA

2023-03-21 Updated: 2023-03-27

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Invasive alien species

Biodiversity

Environmental DNA is an innovative method used to detect different species in the aquatic environment. Similar to barcodes used to identify items at the grocery store, eDNA allows biologists to identify different aquatic species through their unique genetic fingerprint. By releasing cells and other biological material such as skin particles, mucus, urine and feces into the environment, scientists are able to identify a species with its eDNA.

Why using it?
This method is efficient and fast for scientists. eDNA detection requires little equipment in the field and allows for early detection of the species. A single water sample is all scientists need to determine the presence or absence of an aquatic species of interest. It can also provide real-time results when aquatic invasive species management measures are implemented.

eDNA at the service of the St. Lawrence River
The St. Lawrence Action Plan’s scientists are increasingly using eDNA in their research projects to improve the detection of aquatic invasive species.

The process is simple. After eDNA extraction in the laboratory, scientists can decode the sample's DNA to obtain a sequence or code. The resulting sequence can then be compared with a public database to determine which species have left DNA traces in the sampled environment.

The data collected is shared between the federal and provincial governments to allow for knowledge sharing and thus advance scientific research on aquatic invasive species and the protection of species at risk.

eDNA: a method with its limits
Although eDNA detection is useful in screening for rare or harder-to-locate species, other analytical methods are needed to determine if an established population or species exists in an ecosystem.

eDNA results should be considered with caution, as some detections may prove to be false (false positive), especially in the case of contamination during field or laboratory manipulations. To be valid, an eDNA detection must therefore be combined with the discovery of living individuals (larvae, juveniles or adults).

Although eDNA cannot replace traditional sampling methods, it is another tool that can lead to new discoveries and increase the speed of the detection process.

For more information on ADNe method, consult this research document devopped by St.Lawrence Action Plan parterns.