MERG - Universitetet i Oslo

MERG
Fungal speciation
Objectives of the project
The main objective in this project is to analyze mechanisms and processes involved during fungal
speciation employing empirical and experimental inferences. More specific aims are to:
• Analyze the geographic component of speciation in fungi (allopatric, parapatric vs. sympatric
speciation).
• Evaluate the importance of ecological differentiation and isolation during fungal speciation.
• Analyze the importance of post-zygotic isolating mechanisms.
• Evaluate the importance of hybridization and reinforcement (Darwinian speciation).
Project summary
Although more than 100.000 fungal species exist, fungi are largely missing
in the speciation debate. Speciation theory is based mainly on research on animals and plants and little
is known whether fungi conform to general models of speciation. Four different boreal/nemoral wooddecay
species complexes (Basidiomycota) will be used as model organisms in this project, selected
because multiple breeding units (intersterility groups) exist within the species complexes, indicating
ongoing or recent speciation. Preliminary data indicates that hybridization and/or introgression occurs
in at least two of the species complexes. One main research topic is to reconstruct speciation
mechanisms in fungi through biogeographical interpretation of phylogenies (phylogeography) based on
multilocus DNA datasets. The ecological component of the speciation process will be studied through
various physiological experiments. Various fitness parameters and ecological characteristics will be
investigated in the divergent allopatric/sympatric lineages and coupled to the phylogeographic
information obtained. Various post-zygotic isolating mechanisms will be investigated, including
chromosomal incongruence. In this way we also want to illuminate to what extent the frequently used
pre-zygotic clamp connection formation criterion reflects reproductive isolation. Results from some
studies indicate that reinforcement may be an important speciation mechanism in fungi. The importance
of hybridization and reinforcement during fungal speciation will be investigated through the analyses of
hybrid zones and mating experiments between allopatric/sympatric populations. The team behind this
project together shares the expertise and experience needed to carry through all of the proposed
subprojects.
The team
Tor Carlsen (Post Doc), Inger Skrede (Post Doc), Kristian Seierstad (PhD), Håvard Kauserud, Glenn-
Peter Sætre (CEES) + external collaborators.
12
From left: Fruit bodies of Amanita
muscaria (Photo: Arve Græsdal) and
Hypholoma fasciculare (Photo: Per
Marstad)