We focus on understanding the origin, evolution and regulation of sexual development and sex determining systems. We use the brown algae as model organisms. We exploit their spectacular diversity of patterns of sexual developmental, reproductive and life cycle features, and their amenability for genetic, genomic and molecular evolutionary approaches. The algae have played a prominent role in the emergence of multicellularity over the course of evolution, and we are also investigating the molecular basis and the evolution of their complex body patterns. Our research lines are supported by an investment in the development of tools and resources for the brown algae, in collaboration with the brown algal research community.