Leeches To Track Mammal DNA In Jungles
April 24, 2012

Leeches To Track Mammal DNA In Jungles

Connie K. Ho for RedOrbit.com

Researchers from Copenhagen Zoo and the University of Copenhagen have discovered a way to track mammals in the jungles of Southeast Asia. Scientists collected leeches from the jungles to analyze the blood and DNA of animals taken by the parasites. With this new method, researchers will be able to study the biodiversity of the mammals without having to track each one down.

The findings, to be published in science journal Current Biology, allow scientists to break away from traditional methods such as collecting hair or feces, following tracks, and utilizing cameras.

"It is not unusual that unknown mammals appear on local markets and end up in soup pots — without scientists knowing of it. Therefore, the new method is important to obtain knowledge of what hides in the jungle - regarding both known and unknown species. I am convinced that the new method is not only useful in Southeast Asia, but can be used in many other parts of the world where such leeches exist," explained Tom Gilbert (www1.bio.ku.dk/english/staff/profile/?id=295003), professor at the Center for GeoGenetics at the University of Copenhagen and one of the initiators of the project together, in a prepared statement.

Veterinarian Mads Bertelsen states the new method was developed through another project.

"It was in a Zoo project in Malaysia on monitoring and tracking of tapirs that we started thinking about the possibilities. Leeches in the jungle attacked one of my colleagues, and the idea was born. Then we contacted DNA researchers at GeoGenetics, University of Copenhagen, to explore the perspectives directly. First, we used 20 medical leeches fed with goat blood from the Zoo. It turned out that the leeches contained traces of goat DNA for more than four months after eating. Then we knew we were on to something," remarked Bertelsen, another initiator of the project, in the statement. "It is an alternative way of monitoring mammalian wildlife. Leeches come to you with the blood samples, rather than you tracking down the animals in the jungle. Simple and cheap, and the sampling does not require specially trained scientists, but can be carried out by local people. I am convinced that this technique will revolutionize the monitoring of threatened wildlife in rainforest habitats.”

After figuring out how to utilize the leeches to their advantage, the researchers took steps to collect leeches from a Vietnamese rainforest. 21 of the 25 leeches had DNA from mammals, including those of rare species. They were able to find animals like the Annamite striped rabbit, which hasn´t been seen since 1996.

"I was very surprised and happy when I saw the first results from the DNA analyses of the leeches. We kept finding new DNA sequences from local Vietnamese mammals, only from analyzing very few leeches. The new method could become very important for gaining knowledge on threatened mammals," commented Dr. Philip Francis Thomsen in the statement. "It could give us insight to which mammal species are present in a given area, including new and unknown species. The recent revolution in DNA-sequencing technology, combined with a simple but innovative idea, has made this possible.”


Image Caption: Veterinarian Mads Bertelsen and PhD student. Philip Francis Thomsen