By combining existing methodologies scientists have developed an effective way of using non-invasive samples from elephant dung to generate genome-scale data. (Photo: iStock)
By Shaun Smillie | 12 Jan 2023
Every pile of elephant dung holds a story that tells of forgotten migrations, ancient hookups and a population’s well-being, and now scientists are unlocking these secrets thanks to a new way of collecting DNA.
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It used to be that when scientists needed to collect DNA from a wild elephant, it required a dart gun, lots of money and a good dollop of bravery.
Then, once those blood samples had been gathered, there were the added complications of securing proper refrigeration in which to store them and having chemicals at hand that were dangerous to handle.
Recently, researchers from the universities of Illinois Urbana-Champaign and Pretoria pioneered an inexpensive alternative that involves the use of treated, postcard-sized, data collection cards.
Dung samples are smeared on those cards and can be kept for months without refrigeration.
“We combined existing methodologies in such a way that we are now able to use non-invasive samples to generate genome-scale data,” said Alida de Flamingh, in a statement. She is a postdoctoral researcher at the University of Illinois Urbana-Champaign in Illinois, US.
“This allows us to assess wildlife populations without having to dart, capture or immobilise animals,” she said.
The team’s research appeared in the latest issue of the journal, Frontiers in Genetics.
Collecting DNA from elephant poop is not new, but it has its challenges.
De Flamingh came up with this approach after working with co-author Ripan Malhi, whose laboratory focuses on ancient DNA.
Extracting DNA from source material that is sometimes tens of thousands of years old is difficult. But ancient DNA laboratories have pioneered ways of collecting this genetic material.
“Ancient DNA can be problematic because samples are degraded and may yield very low levels of target species DNA,” De Flamingh explained.
“Obtaining genomic data from dung can be similarly challenging, with lower elephant DNA concentrations than are available from blood samples. I thought, this sounds like an excellent opportunity to test whether the same methodologies can be applied to non-invasive samples to generate the same type of data.”
To test their new technique, the team at first turned to collecting samples from zoo elephants. They wanted to see how fresh the dung needed to be to provide genomic data.
The subjects in this experiment were African savannah elephants from the Jacksonville Zoo and Gardens in Florida and the Dallas Zoological Gardens.
The researchers would retrieve the dung immediately after defecation, then after 24, 48 and 72 hours.
What they found was that even three-day-old faeces had enough DNA to study.
The team then moved their experiment to Africa.
Co-author of the study, Prof Rudi van Aarde, of the department of zoology and entomology at the University of Pretoria, and his colleagues used the cards to collect elephant dung across southern Africa.
And it worked — even better than expected.
The collected samples didn’t just provide elephant DNA, but also genetic material from microbes, plants and parasites.
This data provided details about the elephant, the microbial composition of its gut, habitat and diet.
They were even able to detect the DNA of butterflies that had landed and fed on the dung after the elephant had left.
With the use of satellite tracking, the study will, Van Aarde believes, assist in identifying different elephant populations and help scientists see how they are related to one another.
“This could help in developing corridors to restore those associations and provide a new positive platform for conservation in Africa,” Van Aarde told Our Burning Planet. In the future, the examination of the poo left by other animals might help scientists to also delve into their hidden lives.
But for Van Aarde, who has spent decades studying elephants, this new technique offers a lot.
“We can actually pick up on disease and health and all these details on elephants. Using all these wonderful, lovely new technologies, the benefits this will have for conservation are going to be endless.” DM/OBP
https://www.dailymaverick.co.za/article ... servation/
Lis, very interesting!
