Although the international ivory trade was banned in 1989, the levels of illegal elephant killings continue to rise, estimated to be in the tens of thousands in 2011 alone, according to statistics from Monitoring the Illegal Killing of Elephants. Some estimates go even higher. As the ivory trade thrives, researchers are testing new ways to pinpoint where the illegal ivory is coming from in an attempt to aid antipoaching efforts.
Nicholas Georgiadis, of the Puget Sound Institute, says researchers originally hoped that if elephants had DNA structures similar to some other animals, such as giraffes, then it would be easy to decipher where ivory had come from. But that didn’t prove to be the case.
Between the African savanna and rainforests, two elephant species developed over millions of years. But the genetic markers within each of those species are very similar. Thus, it is difficult to detect where ivory came from by analyzing DNA. “It’s not straightforward, so you need much more information to know where a tusk is from,” Georgiadis says.
Researchers led by University of Illinois Assistant Professor Alfred Roca have looked at mitochondrial DNA (mDNA), taken from within a cell, rather than just nuclear DNA which was more traditionally studied. The mitochondria are the part of the cell that generates most of the cell’s chemical energy. Looking at mDNA is a breakthrough because it is only passed down by females, and unlike male elephants, females do not migrate outside of the herd. So while other genetic markers are spread across the landscape, “the mitochondrial DNA and any mutations in the mitochondrial DNA end up being bound to the herd,” says Roca.