My research is focused on applying population genomic tools to empirical data sets and developing such methods. I have worked with a number of different systems across the plant and animal kingdoms but my main subjects have been Arabidopsis thaliana and humans so far. Some of my main research foci are outlined below. Recent papers can be found under publications.
European population history using ancient DNA
Currently, I am involved in a number of projects concerned about the European prehistory. My main interest lies in understanding human migrations, how different prehistoric groups interacted with each other and how all of this eventually relates to modern populations. DNA extracted from radiocarbon dated human remains are a powerful tool for such purposes as we know the genotype from a sample, when it lived and where it lived or at least died. This is quite important as there are limits to what you can infer from genomic data obtained from modern individuals. I really like this time capsule part of the work. The specifics of working with ancient DNA (e.g. degradation, low coverage, potential contamination) always require special care and they also make the use of many methods used for modern data impossible, which is why I also keep thinking about new ways how to analyze aDNA data.
Methods for detecting natural selection
I think it is interesting how populations of a single species can occur in various different environments. While these populations only show minor differences on a genome-wide average, they can show strong differentiation at loci involved in adaptation to the particular environments. There are various approaches to find such loci, one of them includes using actual environmental variables to look for correlations between allele frequencies and the environment. It is important, however, to account for some sources of noise and even potential biases such as low sample size and population history. I have been involved in designing approaches which either use ancient data (see above), environmental various from various populations or haplotype information.
Population genomics of Arabidopsis thaliana
Arabidopsis thaliana might be a quite insignificant weed, but it became the main model plant. It is found all across the Northern hemisphere (and in some parts of the Southern) which means that it has spread and adapted to a wide range of different environments. Partly included in the 1001 genomes project, I investigated the signature of these processes on various different levels: (i) the general effects on genome diversity and population structure, (ii) the enrichment of slightly deleterious alleles due to recent bottlenecks in some populations, (iii) adaptation to local environments and (iv) the genome-wide signal of dealing with nitrogen limitations in plants.