Because DNA is a tiny molecule found within the cells of living creatures (along with other molecular bits and bobs), you need special tools to pick up it up.
We collect eDNA from water
A common method for collecting DNA is to use a special collection kit that filters water and extracts the DNA from material captured on the filter. Our kits contain a large syringe with a filter that captures particles containing eDNA. Preservative is then injected into the filter capsule to keep the DNA fresh while it is transported to the laboratory for analysis.
The kits are made in Aotearoa New Zealand, and all samples are processed and kept here.
Watch the video on how to take an eDNA sample.
The eDNA is analysed in a lab
A scientist takes the sample from the filter, and extracts and multiplies the DNA using a series of procedures.
Once the DNA is isolated, special molecules called primers are released into the mixture to scan the DNA strands for a unique region called a barcode.
These primer molecules can pick up different things while they are scanning. For example, some will only bring back information on plant DNA, while others are specific to animals.
The barcodes are used to identify different species.
The eDNA is matched to species
We know the sequence of components that make up the DNA barcodes of different species (by taking samples of DNA from physical specimens and sequencing their barcodes), and there are databases that convert DNA barcodes into a list of species.
It is similar to developing a barcode scanner at a supermarket to identify food items. Just like the checkout, we can match the DNA barcodes to species in the database to get a list of all the wild things. Many species are not yet represented in the databases, and is called eDNA ‘dark matter’. It is not uncommon that an eDNA sample will contain this dark matter.