Selective Sweep Analysis
Genes that have been subject to recent positive selection are expected to leave a genome signature of loss of polymorphism around the selected locus (called "selective sweep"). This can potentially be used to do systematic genome screens for genes involved in recent adaptations. We are focussing on natural populations of the house mouse (Mus musculus) for identifying such genome signatures as well as studying underlying gene functions. Since mouse populations have expanded across the whole world in several waves, it is possible to compare populations at various levels of divergence, including very recently separated populations (a few hundred to a few thousand years), as well as longer separated ones (up to one million years).
Status of the project
In 1997 we developed the idea to use microsatellite polymorphism for systematically detecting selective sweeps and have published a proof of principle experiment using Drosophila populations (Schlötterer et al. 1997). We have since then developed the mouse system for this approach and published two systematic microsatellite screens, making use of the increasingly better availability of genomic resources (Ihle et al. 2006; Teschke et al. 2008). We have also used the Affymetrix Genome Diversity SNP arrray for genome-wide screens for selective sweeps (Staubach et al. 2012). From these data we could infer that selective sweeps happen frequently in natural populations, at a mimimum rate of one every 50 generations. In addition, we have now long lists of candidate genes that await further characterization.
One project for the analysis of an adaptive trait gene deals with the gene Dmrt1 (Doublesex and mab-3 related transcription factor 1) which was found to show a strong selective sweep signature between two wild mouse populations (Mus musculus domesticus), from Germany (Cologne/Bonn) and France (Massif Central). We have identified a candidate mutation in this gene which might lead to a change of regulation in some target genes and we are currently analysing this in molecular detail.
The project was initiated by Sonja Ihle in my former laboratory in Cologne and was continued by Meike Teschke and Fabian Staubach. The work on Dmrt1 is currently being conducted by Natascha Hasenkamp (PhD student). Postdoc applications for joining this work are welcome.
Selected publications in the context of this project
- Schlötterer, C., Vogl, C., Tautz, D. (1997). Polymorphism and locus-specific effects on polymorphism at microsatellite loci in natural Drosophila melanogaster populations. Genetics, 146, 309-320.
- Ihle, S., Ravaoarimanana, I., Thomas, M., Tautz, D. (2006). An Analysis of Signatures of Selective Sweeps in Natural Populations of the House Mouse. Molecular Biology and Evolution 23, 790-797.
- Teschke, M., Mukabayire, O., Wiehe, T., Tautz, D. (2008). Identification of selective sweeps in closely related populations of the house mouse based on microsatellite scans. Genetics 180, 1537–1545.
- Staubach F, Lorenc A, Messer PW, Tang K, Petrov DA, Tautz D. (2012). Genome Patterns of Selection and Introgression of Haplotypes in Natural Populations of the House Mouse (Mus musculus). PLoS Genetics (in press)