Dioecy, which is a plant breeding system with separate male and female individuals, is rare and only found in approximately 6% of all flowering plant species. Despite being rare, it has a scattered taxonomic distribution and appears in about 75 % of all plant families, suggesting that this breeding system has evolved repeatedly throughout the history of flowering plants. Although genetic sex determination in animals is well-understood, the phenomenon is far less well-understood in plants. During the last decade, however, major progress has been made and it has become apparent that sex determination systems in plants are strikingly similar to those found in animals. This suggests that the evolutionary processes and selective forces, leading to the evolution of genic sex determination, are similar for these different groups. Several instances of true chromosomal sex determination have been described in plants and the diversity of plant chromosomal systems mirror those found in animals. These ranges from the most primitive forms, where sex is determined by a single locus, to cases with true heteromorphic sex chromosomes, i.e. sex chromosomes that are morphologically distinguishable by microscopy. Sex chromosomes in plants are evolutionary young and therefore particularly interesting to study, since they may provide insights in early sex chromosome evolution.
My research focuses on the evolution of sex chromosomes in Populus where I use whole-genome sequence data of Populus tremula (European aspen) to fine-map the region surrounding the sex determining genes in Populus. My aim is to identify whether these loci are surrounded by a region with suppressed recombination and if so, how large this region is. A more practical goal is also to develop sex-specific markers that can be used to sex individuals with high accuracy at an early age. Since the sex determining system in Populus appears to be relatively young, without morphologically distinct sex chromosomes, it will be very interesting to study the patterns of genetic variation in the regions harboring the sex determining loci (the neo-sex chromosomes). It is likely that such studies will provide important insights into the very early stages of sex chromosome evolution.
My scientific background lies in the field of plant ecology where I foremost have an interest in the evolution of plant breeding systems and sexual dimorphism in plants. I have previously been working with questions concerning sexual dimorphism and reproductive costs in Silene dioica.