Lab Members: Stefan Zoller

Photo: Gabrielle Schweizer

Stefan Zoller (Postdoctoral Research Associate)

Department of Botany
The Field Museum

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

Interesting links:
– High Performance Computing at the Field Museum, Chicago
– Pritzker Lab at the Field Museum, Chicago

Research Interests:
Evolution, population biology, conservation biology of lichens.
Computational biology.

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.

2000: $21500 Swiss National Science Foundation (SNF); Investigation of mechanisms involved in accelerated evolution: a population genetic approach using the Omphalina (Basidiomycetes) model system.
1992/3: $2500 Swiss-Mobil Student Exchange Scholarship; Studies at the Botany Department of the University of Lausanne

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

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

Walser J.-C., S. Zoller, U. Buchler, C. Scheidegger (in press) Species-specific detection of Lobaria pulmonaria (lichenized ascomycetes) diaspores in litter samples trapped in snow cover. Molecular Ecology

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

Scheidegger C., S. Flachsmann, S. Zoller, B. Frey (1997) Naturschutzbiologie bei Flechten: Konzepte und Projekte. Kleine Senckenbergische Reihe 27:167-175.

Tanner K.M., & S. Zoller (1996) Zum Ausmass von Landschaftsveränderungen durch Meliorations-Eingriffe. Eine vergleichende Untersuchung in den Gemeinden Wintersingen, Arisdorf und Ormalingen (Kanton Basel-Landschaft). Regio Basiliensis 37:155-166

Tanner K. M., & S. Zoller (1996) Zur Veränderung von Landschaftsstrukturen durch Meliorationen. Fallbeispiel Wintersingen (BL). Vermessungskunde, Photogrammetrie und Kulturtechnik 94:107-111

Scheidegger C., B. Frey, S. Zoller (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