By Jason Koebler
Forensic DNA scientists have learned that a large majority of elephants being poached for ivory in Africa are killed in a small number of “hotspots.” If poaching can be controlled in those areas, the thinking goes, there may be a huge decline in the number of illegally-killed elephants worldwide.
“There’s not that many places where elephants are being poached,” Lisa Brown, a data analyst at the University of Washington. Hers is one of the only labs in the world using DNA to identify where elephants are being killed. “The same populations keep recurring in our DNA assignments, which implies that there are locations that supply hundreds of elephants worth of ivory, repeatedly over time.”
Here’s how it works: Brown and her partner, Samuel Wasser, who started the University of Washington project, take samples of elephant DNA—either from feces or tissues, from spots around Africa. That DNA is then sequenced and analyzed at 16 different spots which are known to be highly variable between populations. Elephant DNA varies highly between forest populations and savanna populations, and often varies within those two groups depending on location. Brown said that, over many generations, certain populations have built up genetic mutations that don’t affect an individual elephant’s livelihood or ability to reproduce. That makes them easy to geographically pinpoint genetically, but impossible to do it based on physical traits.
“The mutations accumulate, but it doesn’t affect the elephants, but we’re able to look at them to tell the difference between populations,” she said.
When there are major ivory busts, her lab receives samples of roughly 200 tusks. The lab then sequences the DNA of those tusks and compares it to the DNA library they already have, looking for a match. They are able to decipher where a particular elephant was killed to within 250 kilometers. That may not seem too close, but Brown says that it’s “often less than the distance separating most protected areas” in Africa, meaning researchers can identify which park an elephant was killed in.
The lab is also able to tell how accurate their guesses are. Their data is better for forest elephants, especially in the western part of the continent, and are highly accurate. For savanna elephants, genetic matches are often more difficult to make. More....