Copy-Number Evolution

Copy number variants are often defined as segments of DNA that are 1 kb or larger and present at a variable copy number in comparison to a reference genome. They can be insertions, deletions and duplications and can encompass one or more genes. They are very common in the genome and possibly constitute the biggest contribution of variation in genomic sequence among individuals: in mice and humans, CNVs affect up to 12% of the genome.
Given the abundance, size and mutability of CNVs they might contribute to phenotypic variation, including rapid adaptations. We hypothesize that due to these features CNVs may be involved in early stages of population differentiation, and aim to understand the dynamics of copy number variation in the context of adaptations.

Status of the project

We have shown that copy numbers at some specific loci become highly unstable in hybrid crosses between M. m. domesticus and M. m. musculus, which might contribute to the reproductive isolation effects seen across the hybrid zone of these subspecies (Scavetta and Tautz, 2010).
In another project, we have systematically assessed the role of CNVs in causing expression differences between populations of M. m. domesticus. We have identified several CNVs with diagnostic copy number differences between the populations and found for some of them that they are associated with selective sweeps. A publication on these results is in preparation. This work was done by Jarek Bryk, who has in the meantime moved to the National Centre for Biotechnolgy Education, University of Reading.
In a current project, we assess whether CNVs might also be involved in adaptation effects occurring within a few generations. We have set up appropriate experiments in which environmental conditions were changed for mice from a natural populations as well as an inbred strain. The results will be evaluated by whole genome sequencing approaches. This work is currently being conducted by Zeljka Pezer (postdoc).

Publication in the context of this project

Scavetta, R.J. & Tautz, D. (2010): Copy number changes of CNV regions in intersubspecific crosses of the house mouse. Molecular Biology and Evolution 27: 1845-1856