DNA reveals families of Asian elephants

The research team examined DNA from twenty-seven elephants, originating from almost the entire range of the species. The results show that there are four genetically distinct clusters: Borneo, Sumatra, Sri Lanka, and the Asian mainland. This is the first time that genome data have validated that the Sumatran elephant is a separate subspecies.

“Our study shows that the current subspecies classification of the Asian elephant corresponds with what we observe in the genome,” says Jeroen Kappelhof, PhD researcher at Wageningen University. “This knowledge helps conservationists and zoos to act more purposefully in preserving the species.”

“The genetic material literally allows us to reconstruct the family tree of the Asian elephant,” Kappelhof explains. “We see that their common ancestor split into two branches about 170,000 years ago: one towards Borneo and Sumatra, and one towards Sri Lanka and the Asian mainland. Shortly afterwards, Borneo and Sumatra each went their own way. Much later, around 48,000 years ago, Sri Lanka and the mainland also separated from each other.”

Importance for conservation

The Asian elephant is listed as Endangered on the IUCN Red List. Some subspecies, such as the Sumatran elephant, are even Critically Endangered. Now that the genetic differences have been mapped more clearly – using methods from conservation genetics that apply DNA research to the preservation of species – conservationists can develop more effective strategies, for example by limiting inbreeding or managing populations separately.

Collaboration between science and zoos

A special aspect of the study is that many DNA samples came from animals living in European zoos. These zoos, united in the European umbrella organisation EAZA, provided blood samples that are stored in the joint EAZA Biobank. Rotterdam Zoo (Diergaarde Blijdorp) plays a leading role by managing the European studbook (EEP) of the Asian elephant and coordinating genetic management in European zoos. Thanks to this collaboration, a complete overview of genetic variation could be compiled.

The analysis shows that the population in European zoos is genetically diverse. This offers opportunities for preserving diversity, provided that breeding is carefully managed per genetic cluster. The results are therefore relevant for both management of wild elephants and breeding programmes in captivity.

Future research

Although the genetic status of the Sumatran and Bornean elephant is now firmly determined, questions remain about, for example, the exact origin of the elephants on Borneo and Sri Lanka. Kappelhof emphasises that further research is needed to piece this puzzle together. “The better we understand the genetic history of elephants through evolutionary genome science, the better this knowledge can be used to strengthen their protection,” says Kappelhof.

More information

• The results of this study were recently published in the scientific journal Ecology and Evolution, titled 'Genomics Reveals Distinct Evolutionary Lineages in Asian Elephants’.

Text: Jeroen Kappelhof and Cecile Leuverink, Wageningen University & Research
Images: Jester&Wylde