2018/01/11

Theguardian January 8, 2018: Rhinoceros DNA database successful in aiding poaching prosecutions

A large database of rhinoceros DNA is successfully being used to prosecute poachers and those trading rhino horns, new research has revealed.

While numbers of the southern white rhino – the only wild subspecies of white rhino in Africa – have grown to about 20,000, fewer than 5,500 black rhinos are thought to exist in the wild, and both species are affected by poaching.

The animals’ horns are traded for their use in traditional Asian medicines, and poaching is soaring – in part as a result of rumours that a former politician in Vietnam was “cured of cancer” using a rhino horn remedy. Figures for 2016 suggest that poachers killed more than 1,050 rhinos in South Africa alone.

Now researchers working on DNA-based forensic testing have shown just how powerful the technique is in fighting the illegal trade and bringing criminals to justice.

“Based on a really solid number of animals, both white and black rhinos, we can get solid match statistics to show ‘that’ horn is definitely from ‘that’ carcass,” said Dr Cindy Harper, a co-author of the study from the University of Pretoria in South Africa.

The set-up, known as the Rhinoceros DNA index system or RhODIS, was established in 2010, and currently contains more than 20,000 rhino samples from living animals, stockpiled horns and forensic cases – such as poaching.

The authors say the latest study shows just how powerful the database is in linking forensic evidence to particular animals.

Published in the journal Current Biology, the researchers describe how they selected samples from 3,085 white rhinos and 883 black rhinos from the database and examined their DNA, comparing the number of times particular patterns are repeated at certain locations in their genomes.

“It is similar to human DNA profiling for forensic cases now,” said Harper, pointing out that the team looked at repeated patterns at 23 locations in the genome.

The results not only reveal that black rhinos fall, as currently thought, into three subspecies, and wild white rhinos into one, but also sheds light on the genetic variation within different populations.

Moreover, the team were able to use the genetic data from the 3,986 rhinos to calculate the probability that a match between a forensic sample and a particular rhino could crop up by chance. more