- population differentiation and speciation
- clonal reproduction
- adaptation and interaction
I use an integrative research approach that includes molecular techniques in combination with ecological investigations and behavioral experiments and different animal model systems:
The Amazon molly - Poecilia formosa
The Amazon molly, Poecilia formosa is my main model for studying the evolution and maintenance of clonal reproduction. It is an all-female hybrid species and reproduces gynogenetically, i. e., it produces unreduced diploid eggs but needs sperm from a closely related sexual species to trigger the onset of embryonic development. Usually, the male genetic material is excluded from the oocyte and does not contribute to the offspring (clonal reproduction). Clonal vertebrates are generally thought to be evolutionarily young, slow to evolve and due to the lack of recombination very vulnerable to accumulation of mutations. There is, however, evidence that despite its clonal reproduction P. formosa is quite successful ecologically and also much older than expected. The questions I am interested in the system are therefore, how can unisexuals survive in rapidly changing environments and successfully compete with closely related sexual species.
Coral and their symbionts
Tropical coral reefs are among the most diverse and economically important ecosystems but face severe environmental threats that are very often directly or indirectly anthropogenically induced. The potential to adapt to these changing environmental conditions is based on genetic variability. I am therefore conducting several studies on different reef building cnidarians that describe genetic diversity at different organisational levels (within and between species, populations, individuals). Additionally, I am looking into population (re-)colonization and connectivity but also into cryptic species and dispersal patterns. Our projects also include studies of the symbiotic algae Symbiodinium, an important factor in colony survival.
Because Daphnia can switch between clonal and sexual reproduction they are interesting models to test the advantages and disadvantages of clonal reproduction and the adaptability of clonal populations. We investigate factors (mainly predation and CO2) that influence the genotypic Variability in natural and artificial Daphnia populations.
Molecular methods are recently also used more and more in conservation contexts. In co-operation with consultants for landscape planning committees we collect molecular evidence for the presence/absence of endangered/protected species (e.g. wild cats). We investigate the origin of (re-)invading fish species and give advice to re-introduction projects. In addition to DNA evidence from tissue samples, hair, feathers or dung we also use eDNA to e.g. test for the presence of crested newt in local ponds.