An international team led by scientists at the University of Washington have used DNA to identify three major networks responsible for smuggling large shipments of ivory out of Africa.
In a study published online September 19 in Science Advances, the team demonstrated an approach they hope will help catch and convict international ivory traffickers.
Dr. Bruce Weir of the Department of Biostatistics within the University of Washington School of Public Health co-authored the article. The study was led by Dr. Samuel Wasser, a professor of biology at the UW and director of the University’s Center for Conservation Biology.
Researchers sorted and analyzed the DNA of a sample of elephant tusks found in 38 ivory shipments seized by law enforcement between 2006 and 2015. This allowed scientists to identify tusk pairs that had been separated after poaching and sent in different shipments to destinations around the world.
Researchers then used DNA from elephant dung across the African continent and compared that with DNA from the ivory of seized contraband to determine the elephants’ geographic origins. They found that the tusk pairs were shipped out of the same port, nearly always within 10 months of each other, with high overlap in the geographic origins of tusks in the matching shipments.
Using this protocol, the team identified what appear to be the three largest ivory smuggling cartels in Africa, operating out of Mombasa, Kenya; Entebbe, Uganda; and Lomé, Togo.
Tusk samples between seizures were considered a match if they had identical genotypes, confirmed by 10 or more genetic markers. Researchers then quantified the evidentiary strength of each match.
“As a biostatistician on the study, I helped to answer questions such as: Is it a coincidence that we see matching tusks or is it really meaningful? If two tusks look to be the same genetically, is that true or could they in fact be siblings or parent-child?” said Dr. Weir, professor of biostatistics at the UW School of Public Health and adjunct professor in genome sciences. “Our analyses strongly support the pairs of matching tusks coming from the same elephants.”
The method described in this paper can be used to help law enforcement combat the illegal ivory trade by targeting areas most susceptible to poaching, according to researchers.