Study shakes elephants’ genetic tree

Palaeontologists, after new genetic analysis, are challenging the belief that African elephants belong to one distinct species. 

Researchers analysed mitochondrial DNA of woolly mammoths, African and Asian elephants and Palaeoloxodon antiquus ­– an ancient giant elephant. They discovered P. antiquus is more closely related to the present day African forest elephant, than the African forest elephant is to the African savanna elephant - its nearest living relative.

Professor Alfred Roca, from the University of Illinois and co-author of the study, said: “We've had really good genetic evidence since 2001 that forest and savanna elephants in Africa are two different species, but it's been very difficult to convince conservation agencies that's the case. With the new genetic evidence from Palaeoloxodon, it becomes almost impossible to argue that the elephants now living in Africa belong to a single species."

P. antiquus stood up to four meters tall and weighed as much as 13 tons, more than double the weight of today’s largest elephants. It lived 1.5m to 100,000 years ago before it became extinct, and was present all across Eurasia. The mitochondrial analysis carried out by researchers revealed a shared ancestor of P. antiquus and the African forest elephant lived between 1.5 and 3.5 million years ago. Its closest shared ancestor with the African savanna elephant lived between 3.9 and 7 million years ago. This result was echoed in nuclear DNA studies which were carried out in tandem.

Yasuko Ishida, who led the mitochondrial sequencing and co-author of the study, said: “From the study of bone morphology, people thought Palaeoloxodon was closer to the Asian elephant. But from molecular data, we found they are much closer to the African forest elephant.”

Greater understanding of elephants’ genetic heritage is vital to protect remaining populations. Professor Roca said: “More than two-thirds of the remaining forest elephants in Africa have been killed over the last 15 years or so. Forest elephants are among the most endangered elephant populations on the planet. Some conservation agencies don't recognise African forest elephants as a distinct species, and these animals' conservation needs have been neglected."

The study was published in eLife.