DNA testing on seized ivory shipments that reveals family ties among African elephants killed for their tusks is helping to identify poaching areas and trafficking networks at the center of an illegal trade devastating the population of Earth's largest land animal.

Researchers said Monday they had conducted DNA tests on 4,320 elephant tusks from 49 ivory seizures, totaling 111 tons in 12 African nations from 2002 to 2019. The results could help crack the transnational criminal organizations behind the trafficking and strengthen prosecutions.

"Combining these results with evidence collected from our law enforcement collaborators enables us to collaboratively connect the dots across a massive criminal network," said University of Washington biologist Samuel Wasser, lead author of the study published in the journal Nature Human Behaviour.