Author Interview: eDNAir: proof of concept that animal DNA can be collected from air sampling

PeerJ spoke to Dr. Elizabeth Clare about the recently published article eDNAir: proof of concept that animal DNA can be collected from air sampling Elizabeth is a Senior Lecturer at Queen Mary University of London.


Hi Dr. Clare. Please could you start by telling us a little about yourself and your latest research?

Hi! I’m Dr. Elizabeth Clare. I’m a molecular ecologist, and that means I am interested in using DNA to solve ecological problems. 

We are all shedding bits of DNA all the time. We call this environmental DNA – or eDNA – because you don’t need a visible piece of hair or tissue to collect it. It’s become common to filter eDNA from water to monitor fish populations or search for invasive species. Other people have collected eDNA from snow and the soil. What we wanted to know was whether we could filter eDNA from the air to track the presence of terrestrial animals. 

Why were you interested in this?

My background is working with bats, including in some hard to reach places! One of my co-authors, Dr. Chris Faulkes, works on burrowing animals. We were interested in whether we could use airDNA as a way to assess what species were present in a burrow or a cave when we could not easily see or capture them.  Lots of scientists had speculated about this, but we could not find any published case where someone had actually tested for animal DNA in air. 

What was your methodology?

Our paper describes the first proof of this concept. We have experience filtering eDNA from water so we used a similar method sucking air samples through a really fine filter trying to trap airDNA. We sampled air from inside the artificial burrows of naked mole rats and then in the room the burrows are housed in. We then extracted airDNA from these filters and sequenced a piece of DNA which would let us identify species. 

What did you find? Was there anything surprising about your results?

We compared this DNA against reference databases and identified the naked mole rats but also the humans who care for them. We found the naked mole rats exactly where we expected them to be in the burrows, but also in the room, which shows the DNA moves away from the source. We also found human DNA in all our samples. That was something we had not anticipated. At first we considered this a contaminant, but we then realised it really opens up some interesting questions about how this could be used in archeology or forensic science.

What were the challenges to collecting airDNA?

The biggest challenge we anticipate for future applications of this methodology is the potential for airDNA dilution. In a large space it might be so diluted that we can’t detect it efficiently. We will need to suck lots of air through a filter to accomplish this, but in smaller spaces we think it might work really well. 

Who should be interested in this area of research & why?

I think this is going to be really interesting to scientists who work on animals that are just hard to get to. Roosting in tree hollows, underground, small hard to reach caves etc. It could let us monitor the species present without actually having to disturb them or get really close. However this unexpected side effect of collecting human DNA is also really interesting and we are now discussing what we can do with this sort of technology. 

What are the study’s implications?

Our study suggests we may have another tool we can use in our toolbox to measure biodiversity. We are desperately in need of ways to monitor species on a planetary scale. We think what we have done can be done in remote areas and in hard to reach places, opening up new ways to monitor species. 

But we are aware there are other really serious applications; the same method we used should also be able to identify microbes and pathogens, pollens and fungal spores. It might help us map the transmission of infectious diseases or allergens for example. 

What are your thoughts for future research on this topic? What are the next steps?

The main questions we are now working on are how far can this airDNA travel and how big of a space can we be in and still detect species that are present. We really need to expand the study to consider all the factors which will help preserve or degrade airDNA. That will help us understand its potential uses. 

What impact would you like this research to have?

I really hope other people will go out and try this, and help us narrow down the methods that are going to work the best, and the conditions that are going to make this a really useful tool.  The world is really an ocean of DNA. It’s in the water, the soil and now we know it’s in the air. That’s a huge source of information for us to learn about the planet. This is a really exciting new development and I look forward to seeing what comes next.

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