Rosa mollis/ Rosa villosa
Rosa mollis mainly distributed in Scandinavia and R. villosa found in the Valais (Switzerland) are morphologically extremely similar to each other. We assume that their disjunctive populations represent glacial refugias of a common ancestor covering wide parts of northern and central Europe before the ice age. We are investigating by the help of different molecular markers, whether the lacking re-expansion of both populations after the retreat of the European Ice shield sufficed for a genetic differentiation between R. mollis and R. villosa.
We are also interested in hybridization processes between native Rosa mollis and invasive R. rugosa within a hybrid zone at the Geltinger Birk (Schleswig-Holstein, Germany). We are observing introgression of R. rugosa into the R. mollis population causing a substantial thread for this rare species. We are analyzing genetic consequences and inheritance of morphological characters in both species.
Alexandra Keller (doctoral thesis)