Tracking Rare Fish with eDNA: A New Technique

Want to find rare fish without actually seeing them? Scientists have come up with a clever way using something called eDNA. This stands for environmental DNA, which is basically tiny bits of DNA that living things leave behind in their environment. To detect this eDNA, scientists use a combination of technologies: RPA (which is like a super-fast DNA copier), CRISPR (a tool that can cut DNA at specific spots), and Cas12a (a protein that helps CRISPR find its targets). This combination is so sensitive that it can find even the tiniest amounts of eDNA from rare fish. First, you need to choose a specific DNA sequence (or target site) from the fish you're interested in. Then, you make a special RNA molecule called crRNA, which guides the CRISPR-Cas12a system to the target site. After that, you use RPA to make lots of copies of the target DNA quickly. Once you have the target DNA amplified, you can set up the CRISPR-Cas12a detection system. This system will help you verify if the eDNA from the rare fish is indeed present. The best part? This method works even when there's not much eDNA around. This new protocol is a game-changer for monitoring aquatic biodiversity and protecting rare fish species. It's like having a super-sensitive detective that can find hidden traces of fish, helping scientists better understand and conserve our aquatic world.