Studies of adaptation and speciation in plants are currently experiencing a major revolution. First, new sequencing technologies and conceptual advances open the doors to truly genome-wide analyses of adaptation, selection and genomic divergence in natural populations. Second, the concept of ecological speciation puts ecological adaptation into the spotlight of speciation research because it provides a direct link between ecological adaptation, divergent selection and speciation. To date, however, relevant examples of ecological speciation are scarce and empirical data on the genetic basis of the process is largely lacking.
This project explores the genetic basis of ecological adaptation and its consequences for genome-wide divergence in two plant study systems, an evolutionary young and an older system. The first study system is wild carnation, Dianthus sylvestris, where natural populations occur over a large altitudinal gradient in the Alps and show strong phenotypic divergence in the absence of neutral genetic divergence. This pattern suggests that divergent natural selection underlies phenotypic divergence and has led to ecological adaptation. The second study system includes two closely related Silene species, S. latifolia and S. dioica. These species show incomplete morphological, ecological and reproductive isolation and often hybridize upon secondary contact, yet remain distinct outside of contact zones.
The goal of this project is to gain a novel perspective on links between ecological adaptation, divergent selection and speciation in plants and to provide a test of the ecological speciation scenario. Developing a better understanding of the genetic basis of adaptation and its consequences for genomic divergence and speciation is not only of fundamental interest for basic science, but is also highly relevant for a society that is concerned about the consequences of climate change and associated threats to biodiversity.