Genetic analysis of hybridization and introgression between wild mongoose and brown lemurs
1 Anthropologisches Institut, Universität Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
2 Centre for Conservation and Research, 35 Gunasekara Gardens, Nawala Road, Rajagiriya, Sri Lanka
3 Département des Sciences de la Terre, Université de Mahajanga, Faculté des Sciences, Dépt. de Biologie Animale, B.P. 652, Mahajanga 401, Madagascar
4 Department of Anthropology & Geography, School of Social Sciences & Law, Oxford Brookes University, Gipsy Lane, Headington, Oxford, OX3 0BP, UK
5 Department of Psychiatry, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0603, USA
6 Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK
BMC Evolutionary Biology 2009, 9:32 doi:10.1186/1471-2148-9-32Published: 5 February 2009
Hybrid zones generally represent areas of secondary contact after speciation. The nature of the interaction between genes of individuals in a hybrid zone is of interest in the study of evolutionary processes. In this study, data from nuclear microsatellites and mitochondrial DNA sequences were used to genetically characterize hybridization between wild mongoose lemurs (Eulemur mongoz) and brown lemurs (E. fulvus) at Anjamena in west Madagascar.
Two segments of mtDNA have been sequenced and 12 microsatellite loci screened in 162 brown lemurs and mongoose lemurs. Among the mongoose lemur population at Anjamena, we identified two F1 hybrids (one also having the mtDNA haplotype of E. fulvus) and six other individuals with putative introgressed alleles in their genotype. Principal component analysis groups both hybrids as intermediate between E. mongoz and E. fulvus and admixture analyses revealed an admixed genotype for both animals. Paternity testing proved one F1 hybrid to be fertile. Of the eight brown lemurs genotyped, all have either putative introgressed microsatellite alleles and/or the mtDNA haplotype of E. mongoz.
Introgression is bidirectional for the two species, with an indication that it is more frequent in brown lemurs than in mongoose lemurs. We conclude that this hybridization occurs because mongoose lemurs have expanded their range relatively recently. Introgressive hybridization may play an important role in the unique lemur radiation, as has already been shown in other rapidly evolving animals.