Current address: Metapopulation Research Group, Department of Biological and Environmental Sciences, PO Box 65, FIN-00014 University of Helsinki, Finland.
Phylogeographic patterns in Drosophila montana
Article first published online: 21 DEC 2006
Volume 16, Issue 5, pages 1085–1097, March 2007
How to Cite
MIROL, P. M., SCHÄFER, M. A., ORSINI, L., ROUTTU, J., SCHLÖTTERER, C., HOIKKALA, A. and BUTLIN, R. K. (2007), Phylogeographic patterns in Drosophila montana. Molecular Ecology, 16: 1085–1097. doi: 10.1111/j.1365-294X.2006.03215.x
- Issue published online: 21 DEC 2006
- Article first published online: 21 DEC 2006
- Received 9 July 2006; revision received 26 September 2006; accepted 30 October 2006
- Drosophila montana;
- mitochondrial DNA;
The Drosophila virilis species group offers valuable opportunities for studying the roles of chromosomal re-arrangements and mating signals in speciation. The 13 species are divided into two subgroups, the montana and virilis ‘phylads’. There is greater differentiation among species within the montana phylad in both karyotype and acoustic signals than exists among members of the virilis phylad. Drosophila montana is a divergent species which is included in the montana phylad. Here, we analyse the phylogeography of D. montana to provide a framework for understanding divergence of acoustic signals among populations. We analysed mitochondrial sequences corresponding to the cytochrome oxidase I and cytochrome oxidase II genes, as well as 16 microsatellite loci, from 108 lines of D. montana covering most of the species’ range. The species shows a clear genetic differentiation between North American and Scandinavian populations. Microsatellite allele frequencies and mitochondrial DNA haplotypes gave significant FST values between populations from Canada, USA and Finland. A Bayesian analysis of population structure based on the microsatellite frequencies showed four genetically distinct groups, corresponding to these three populations plus a small sample from Japan. A network based on mitochondrial haplotypes showed two Finnish clades of very different shape and variability, and another clade with all sequences from North America and Japan. All D. montana populations showed evidence of demographic expansion but the patterns inferred by coalescent analysis differed between populations. The divergence times between Scandinavian and North American clades were estimated to range from 450 000 to 900 000 years with populations in Canada and the USA possibly representing descendants of different refugial populations. Long-term separation of D. montana populations could have provided the opportunity for differentiation observed in male signal traits, especially carrier frequency of the song, but relaxation of sexual selection during population expansion may have been necessary.