Complex phylogeographic history of central African forest elephants and its implications for taxonomy

Mireille B Johnson¹^,2 , Stephen L Clifford¹ , Benoît Goossens² , Silvester Nyakaana³ , Bryan Curran⁴ , Lee JT White⁴ , E Jean Wickings¹ and Michael W Bruford²

¹Centre International de Recherches Médicales de Franceville (CIRMF), BP 769, Franceville, Gabon

²Cardiff University, Biodiversity and Ecological Processes Group (BEPG), Cathays Park, Cardiff CF10 3TL, Wales, UK

³Makerere University, Institute of Environment and Natural Resources (MUIENR), P.O. Box 7298, Kampala, Uganda

⁴Wildlife Conservation Society (WCS), BP 7847, Libreville, Gabon

author email corresponding author email

BMC Evolutionary Biology 2007, 7:244doi:10.1186/1471-2148-7-244


Published:	19 December 2007

Abstract

Background

Previous phylogenetic analyses of African elephants have included limited numbers of forest elephant samples. A large-scale assessment of mitochondrial DNA diversity in forest elephant populations here reveals a more complex evolutionary history in African elephants as a whole than two-taxon models assume.

Results

We analysed hypervariable region 1 of the mitochondrial control region for 71 new central African forest elephants and the mitochondrial cytochrome b gene from 28 new samples and compare these sequences to other African elephant data. We find that central African forest elephant populations fall into at least two lineages and that west African elephants (both forest and savannah) share their mitochondrial history almost exclusively with central African forest elephants. We also find that central African forest populations show lower genetic diversity than those in savannahs, and infer a recent population expansion.

Conclusion

Our data do not support the separation of African elephants into two evolutionary lineages. The demographic history of African elephants seems more complex, with a combination of multiple refugial mitochondrial lineages and recurrent hybridization among them rendering a simple forest/savannah elephant split inapplicable to modern African elephant populations.