Looking for animal eDNA in the air

Phil Sansom and Sally Le Page have been speaking with Beth Clare, who is looking to push the field in a whole new direction by looking for eDNA in the air...

Beth - Well, I was writing a report for the government on how we should look at environmental sampling into the future. And I was writing about all the sources of DNA, and I was summarising papers like Eske’s, and thought we should look in water, and we should look in soil, and we should look in leaf litter, and in rain, and in snow, and I said “and in the air!”. And like a good scientist, I went to find the papers to back up all these statements. And I got to the point where I couldn't find one for air, except for some science fair students. And I tried really hard to get in touch with them and I couldn't. And so I said, we should look in the air. And then I thought, well, okay, I'll look in the air.

Sally - How do you go about looking for DNA in the air?

Beth - We've done it a few different ways, but the one we actually published, you know it's the middle of a national lockdown. You can't go anywhere. You can't really do much experimenting, but we had to go into our naked mole rat room to take care of the animals, and they'd been there in their colonies

Sally - In the lab, or just in your house, you have a naked mole rat room?

Beth - No. In the lab, in the university lab. So, we've got the animal care facility and we've got these naked mole rats. They live in a colony. They're really confined. They've been there for many generations. They live in these burrow systems and we thought, okay, if we can get DNA out of the air, that will be the place you can get at first because they have been there for a long time and the DNA is building up in the environment. And a lot of people said, well, that's not going to work because it's too diluted in an air volume. And we sucked air through filters for periods of time from inside the naked mole rat colonies, and then out in the room where those colonies existed, but they weren't actually open. And to our real surprise, it worked on the first try. So, the first filter we sucked air through produced naked mole rat DNA. It also produced human DNA. It produced dog DNA.

Sally - I'm guessing you don't have dogs in your lab?

Beth - No, but one of the animal facility caretakers looks after his mother's dog. And so he was tracking, we think, his mum's dog's DNA into the room with the naked mole rats, and we were sampling it in these forensically trace amounts.

Sally - That is incredible.

Phil - So, it's almost frightening, Beth, how much you can find just from the air, the amount of information you can glean!

Beth - I think so, but we should think of this as a massive opportunity. That idea that you can actually go and survey that way opens up a whole new world of how we might track biodiversity, and the aquatic eDNA people have led the way showing that you can go into oceans and pick up DNA. You know the volume is less of a problem than we thought. And so what we're trying to do now is show that we can replicate that on land and that we don't have to worry too much about terrestrial mammals washing into the water in order to get them, just go after the air they live in and see if you can find them there.

Phil - And would it work outside?

Beth - Out in the wild, that's the next big challenge and something that we're working on right now. It's a big challenge, but it's not an insurmountable one. And, I think we can do it.