PCR tests to protect an endangered mussel


PCR tests to protect an endangered mussel

Biologist Francis LeBlanc prepares to begin his work in the river Little, New Brunswick.

A swab and a tickle in the back of the nose. This is the image that comes to mind when we talk about PCR tests. But these tests are not only used to detect the virus responsible for COVID-19. At Fisheries and Oceans Canada, they are used in particular to protect endangered species.

Each week this summer, scientists will travel to Little River, New Brunswick, to collect water samples. The purpose of the exercise is to check if the river is home to an endangered freshwater mussel species, the Brook Floater.

Instead of visually detecting the mussel, we are able to detect the DNA that the mussel releases into the aquatic environment of the river, explains biologist Francis LeBlanc.

Biologist Francis LeBlanc takes water samples from the Little River.

The filters used during the collection of water samples are stored very carefully by the team of scientists, because they will be sent to the Fisheries and Oceans Canada laboratory in Moncton.

The team of scientists makes sure to keep the filters used during the water sample collection.

Laboratory technicians must then extract the DNA found on the filters brought back from the river. When the water filters, there are also other things that remain captured on the filter, explains technician Chantal Gaudreau. So, we come to do the DNA extraction to make sure we get purified DNA.

The work of technicians, like Chantal Gaudreau, is essential in the PCR test procedure.

It is once the purified DNA has been obtained that the PCR tests come into play. The instruments used to conduct these tests will amplify the DNA of the species being sought, in this case the Brook Floater, to indicate whether the water collected from the Little River showed traces of it.

This step takes about two hours. And the result confirms that the Fisheries and Oceans Canada team was right to be interested in the Little River.

“We are able to see, by the presence of an amplification curve, that we have indeed detected the Brook Floater DNA at the site, which tells us indicates that the mussel is most likely present in the river.

— Francis LeBlanc, Biologist at Fisheries and Oceans Canada

Little River, New Brunswick

And now what? The ultimate goal of the operation is to help preserve the endangered species. By knowing better the distribution of the species and, potentially, the critical habitat, we are able to take measures to protect it, underlines Francis LeBlanc.

PCR tests are also used by Fisheries and Oceans Canada teams to detect pathogens in certain fish and shellfish. They can also be used to assess the presence of an invasive species, such as the green crab.

Because deep down, what is a PCR test? The PCR test is just a way of going to check whether the DNA or RNA of any organism is there or not, replies Francis LeBlanc.

Francis LeBlanc, biologist at Fisheries and Oceans Canada

And since all PCR tests are similar, his team has contributed to public screening for COVID-19 when demand peaked. Our routine work mostly involves pathogens that do not pose a risk to humans; we therefore had to take preventive measures on that side, says Francis LeBlanc. But the bulk of the work, we were highly qualified to do.

In return, the rapid evolution of science during the pandemic also served them. The optimization of methods for detecting COVID-19 using water samples will make the work of identifying invasive species in waterways even more efficient.

At Fisheries and Oceans Canada, as elsewhere, the pandemic has, fortunately, not only had negative effects.


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