eDNA, biodiversity, and the end of brutal field work

eDNA, biodiversity, and the end of brutal field work

I heard a fascinating news clip while listening to BBC radio.

When one wants to study a species and how it is doing or get an idea of what animals live in an area, one usually must spend untold hours in field work. Scientists must come up with clever ways to detect the animals they are tracking, get counts, and collect all kinds of other data. This work is often tedious, expensive, and error prone.

But there is a new technique exploding on both land and sea. It’s called eDNA.

Environmental DNA (eDNA) is a technique that involves simply collecting water or soil samples, then sifting it for DNA. Every living thing sheds DNA into the environment in many ways: skin cells, waste material, hair, scales, etc. Each of these materials has cells, and each of these cells has mitochondrial DNA that identifies the species.

Now, instead of spending long hours trying to canvas areas over long periods of time to see what animals are present, you can simply take a few soil or water samples, and search them for the different species that have been there. Even more amazing, in areas where the mitochondrial DNA doesn’t break down quickly, you can even get a picture of how many kinds of animals lived there in the past.

The technique is perfect for identifying changes in biodiversity. If repeated samples are taken over time, they can tell you if animals are appearing or disappearing from an area. If you want to see if an animal is migrating through an area, simply take samples and see if they appear/disappear at certain intervals.

There are some limitations. You cannot identify individual animals nor get an idea of how many of a particular species are present. Subspecies might have the same mitochondrial DNA and cannot be individually distinguishable.

Still, this is an amazing new technique that will likely revolutionize field work. I’m excited to see what it tells us.

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