This image reveals Elizabeth Clare sampling air to gather airborne DNA. Credit: Elizabeth Clare
” Earlier in my profession, I went to Madagascar hoping to see lots of lemurs. “So, for lots of types it can be a lot of work to discover them by direct observation, specifically if they are evasive and live in extremely closed or unattainable habitats.”
” Compared to what individuals find in lakes and rivers, keeping track of air-borne DNA is truly, really hard, because the DNA appears super watered down in the air,” says Elizabeth Clare, lead researcher of the Queen Mary University of London group (Clare is now at York University in Toronto). “But our zoo studies have yet to fail for different samplers, genes, areas, and speculative methods. All of it worked and remarkably well.”
Bohmann and Clare draw greatly from their past research study monitoring wildlife by collecting other sample types containing DNA shed by animals. This is described as “environmental DNA,” or eDNA, and is a reputable strategy used most regularly to keep track of water organisms by sequencing eDNA from water samples.
” Air surrounds everything, and we wished to prevent contamination in our samples while enhancing true detection of animal DNA,” says Bohmann. “Our newest work with airborne eDNA includes what we typically do when processing eDNA samples, just tuned up a little bit.”
This picture reveals Christina Lynggaard and Kristine Bohmann collect air samples at the Copenhagen Zoo. Credit: Christian Bendix
Each research study group conducted their research study at a local zoo by gathering samples at different places in the zoo, consisting of inside walled-in enclosures like the tropical house and indoor stables, in addition to outside enclosures in the open air. “To collect airborne eDNA, we utilized a fan, like one you would use to cool down a computer, and attached a filter to it. We then let it run for some time,” says Christina Lynggaard, very first author and postdoctoral fellow at the University of Copenhagen.
The fan attracts air from the zoo and its environments, which might consist of hereditary product from any variety of sources, like breath, saliva, fur, or feces, though the researchers have actually not determined the exact source. “It could be anything that can end up being airborne and is small enough to continue drifting in the air,” says Lynggaard. “After air filtering, we drew out the DNA from the filter and utilized PCR amplification to make a great deal of copies of the animal DNA. After DNA sequencing, we processed the millions of sequences and ultimately compared them to a DNA referral database to determine the animal types.”
” Theres a leap of faith part to some of this because when you handle routine tissue or perhaps marine DNA samples, you can determine how much DNA you have, but with these samples were dealing with forensically small quantities of DNA,” says Clare. “In lots of cases, when we just sample for a few minutes we cant measure the DNA, and so we need to jump to the next stage of PCR where we discover whether theres any in it or not. When we sample for hours we get more however there is a tradeoff.”
Clares team from Queen Mary University of London spotted DNA from 25 types of mammals and birds, and even DNA belonging to the Eurasian hedgehog, which is endangered in the UK. These included zoo animals like the okapi and armadillo and even the guppy in a pond in the tropical home, locally taking place animals like squirrels, and insect animals like the brown rat and house mouse. Both groups took extensive steps to examine that their samples were not contaminated, including by DNA already in their laboratories.
By selecting a zoo for the location of their studies, the scientists knew the position of a large collection of non-native species, so they might tell the distinction between a real signal and a contaminant. “We had originally thought about going to a farm, but if you pick up cow DNA you must ask Is that cow here or is it some cow a hundred miles away or in someones lunch?” states Clare. “But by utilizing the zoo as a model theres no other method I would discover DNA from a tiger, except for the zoos tiger. It lets us actually check the detection rates.”
” One thing both our laboratories do is develop and use new tools, so maybe its not so unexpected that we both wound up with the exact same concept at the same time,” states Clare.
Nevertheless, the reality that both research study groups are releasing at the same time in the journal Current Biology is far from coincidental. After seeing each others posts on a preprint server, the 2 groups chose to submit their manuscripts to the journal together collectively. “We decided we would rather take a little bit of a gamble and state were not ready to complete on this,” says Clare. “In truth, its such a crazy concept, were better off having independent verifications that this works. Both groups are really excited to see this technique develop.”
Recommendation: “Airborne environmental DNA for terrestrial vertebrate neighborhood monitoring” by Christina Lynggaard, Mads Frost Bertelsen, Casper V. Jensen, Matthew S. Johnson, Tobias Guldberg Frøslev, Morten Tange Olsen and Kristine Bohmann, 6 January 2022, Current Biology.DOI: 10.1016/ j.cub.2021.12.014.
” Compared to what individuals find in lakes and rivers, keeping an eye on airborne DNA is really, actually hard, due to the fact that the DNA appears incredibly diluted in the air,” says Elizabeth Clare, lead researcher of the Queen Mary University of London group (Clare is now at York University in Toronto). “After air filtration, we drew out the DNA from the filter and utilized PCR amplification to make a lot of copies of the animal DNA. After DNA sequencing, we processed the millions of sequences and eventually compared them to a DNA recommendation database to identify the animal species.”
” Theres a leap of faith element to some of this because when you deal with routine tissue or even aquatic DNA samples, you can measure how much DNA you have, however with these samples were dealing with forensically tiny quantities of DNA,” says Clare. Clares team from Queen Mary University of London identified DNA from 25 types of birds and mammals, and even DNA belonging to the Eurasian hedgehog, which is endangered in the UK.
This picture reveals dingos at Hamerton Zoo in the UK eye air sampling devices with interest. Credit: Elizabeth Clare
The air in a zoo has lots of smells, from the fish used for feed to the manure from the grazing herbivores, however now we understand it is also loaded with DNA from the animals living there. In the journal Current Biology on January 6th, two research groups have each released an independent proof-of-concept study revealing that by sampling air from a regional zoo, they can gather sufficient DNA to determine the animals close by. This might prove to be a valuable, non-invasive tool to track biodiversity.
” Capturing airborne ecological DNA from vertebrates makes it possible for us to discover even animals that we can not see exist,” says scientist Kristine Bohmann and head of the team at the University of Copenhagen.
Terrestrial animals can be kept track of in lots of ways: straight by electronic camera and in-person observation, or indirectly by what they leave, like feces or footprints. The disadvantage to these approaches is that they can include intensive fieldwork and require the animal to be physically present. For instance, keeping an eye on animals by electronic camera needs understanding of where to put the cams on the animals path, sifting through thousands of photos, and typically a little luck.
