DNA analysis indicates that Asian elephants are native to Borneo and are therefore a high priority for conservation.

Prithiviraj Fernando,Edwin Bosi,Raymond J Alfred,T N C Vidya,Annelisa Kilbourn,Geoffrey Davison,Don J Melnick,Michael Stuewe,John Payne,Patrick Andau

doi:10.1371/journal.pbio.0000006

Abstract

The origin of Borneo's elephants is controversial. Two competing hypotheses argue that they are either indigenous, tracing back to the Pleistocene, or were introduced, descending from elephants imported in the 16th–18th centuries. Taxonomically, they have either been classified as a unique subspecies or placed under the Indian or Sumatran subspecies. If shown to be a unique indigenous population, this would extend the natural species range of the Asian elephant by 1300 km, and therefore Borneo elephants would have much greater conservation importance than if they were a feral population. We compared DNA of Borneo elephants to that of elephants from across the range of the Asian elephant, using a fragment of mitochondrial DNA, including part of the hypervariable d-loop, and five autosomal microsatellite loci. We find that Borneo's elephants are genetically distinct, with molecular divergence indicative of a Pleistocene colonisation of Borneo and subsequent isolation. We reject the hypothesis that Borneo's elephants were introduced. The genetic divergence of Borneo elephants warrants their recognition as a separate evolutionary significant unit. Thus, interbreeding Borneo elephants with those from other populations would be contraindicated in ex situ conservation, and their genetic distinctiveness makes them one of the highest priority populations for Asian elephant conservation.

Highlights

Elephants have a very limited distribution in Bornean and other haplotypes unique to ‘Sundaland’ (Borneo), being restricted to approximately 5% of the island in the extreme northeast (Figure 1)
We PCR-amplified and sequenced a 630 bp fragment of mitochondrial DNA, including the hypervariable left domain of the d-loop (Fernando et al 2000), from 20 Borneo elephants and compared them with 317 sequences we generated for elephants across ten of the 13 Asian elephant range states (Figure 2)
All ‘Sundaland’ haplotypes fell in clade b, while a and b clades were observed in Sri Lanka and mainland populations (Figures 3 and 4)

Summary

Introduction

Elephants have a very limited distribution in Borneo, being restricted to approximately 5% of the island in the extreme northeast (Figure 1). Popular belief holds that elephants presented to the Sultan of Sulu in 1750 by the East India Trading Company and subsequently transported to Borneo founded the current population (Harrisson and Harrisson 1971; Medway 1977). These animals presumably originated in India (Shoshani and Eisenberg 1982), where company operations and trade in domesticated elephants were centred. Considering the geographic proximity to Borneo, the elephant trade that flourished in Sumatra and peninsular Malaysia during the 16th–18th centuries (Andaya 1979; Marsden 1986[1811]) may have been the source. If elephants were introduced to Borneo, the source population could have been India, Sumatra, or peninsular Malaysia, and as a feral population, Borneo’s elephants would have low conservation importance

Methods

Results

Conclusion