Ph.D., Botany, University of Bern, 1999
M.S., Biology, University of Zurich, 1995

Research Interests:

Evolution, population biology and conservation of lichens.

Current Research:

My current research, in collaboration with Dr. François Lutzoni, investigates rates of evolution in lichenized and non-lichenized Omphalina species (Basidiomycetes). It has been shown, that transitions from a non-lichenized to a lichenized state were always coupled with an increase in nucleotide substitution rates. Proposed mechanisms involved in these shifts are: (1) a generalised acceleration of nucleotide substitutions resulting from a faster mutation rate, (2) relaxation of selection or (3) positive selection (in particular, frequent selective sweeps). Molecular phylogenetic approaches alone are not sufficient to distinguish among the possible mechanisms. But population genetic theories make predictions on patterns and levels of genetic variation. Therefore, we use a population genetic approach, comparing within-species variation and between-species variation.

This project is supported by a Swiss National Science Foundation Postdoctoral grant.

Publications:

Zoller S., B. Frey & C. Scheidegger (2000) Juvenile development and diaspore survival in the threatened epiphytic lichen species Sticta fuliginosa, Leptogium saturninum and Menegazzia terebrata: conclusions for in-situ conservation. Plant Biology 2:496-504

Zoller S., F. Lutzoni & C. Scheidegger (1999) Genetic variation within and among populations of the threatened lichen Lobaria pulmonaria in Switzerland and implications for its conservation. Molecular Ecology 8(12):2049-2060

Zoller S., C. Scheidegger & C. Sperisen (1999) PCR primers for the amplification of mitochondrial small subunit ribosomal DNA of lichen-forming ascomycetes. Lichenologist 31(5):511-516

Zoller S., J.-C. Walser & C. Scheidegger (in prep.) A PCR-based method for the species-specific identification of lichen diaspores: detection of wind dispersed isidioid soredia of Lobaria pulmonaria trapped in the snow cover.

Lutzoni F., P. Wagner, V. Reeb, S. Zoller (2000) Integrating ambiguously aligned regions of DNA Sequences in phylogenetic analyses without violating positional homology. Systematic Biology 49(4):628-651

Scheidegger C., Frey B. & Zoller S., (1995) Transplantation of symbiotic propagules and thallus fragments: Methods for the conservation of threatened epiphytic lichen populations. Mitteilungen der Eidgenössischen Forschungsanstalt für Wald, Schnee und Landschaft. 70(1):41-62