Marcel E. Dorken
Assistant Professor
Research interests:
Evolution of reproductive strategies
Evolutionary transitions from one form of reproduction to another are
associated with key changes in the ecology, life-history and genetic
structure of plant populations. I am interested in two of these
transitions, the evolution of separate sexes (dioecy) from combined
sexes (hermaphroditism), and the evolution of asexuality from sexual
reproduction. Most of the ongoing projects in the lab involve the
first of these transitions, the evolution of separate sexes, which
has occurred at least 100 times in the flowering plants alone. We use
a combination of field work, manipulative experiments, and genetic
marker studies to examine how and why unisexuality has evolved in
this group.
Teaching
Biol 3170H: Plants and their Ancestors
Biol 3190H: Wild Plants of Ontario
Biol 4610H: Evolutionary Ecology
Selected publications
Perry, L. E. & M. E. Dorken (2011) The evolution of males: support for predictions from sex-allocation theory using mating arrays of Sagittaria latifolia (Alismataceae). Evolution (in press).
Dorken, M. E., & W. E. Van Drunen (2010) Sex allocation in clonal plants: might clonal expansion enhance fitness gains through male function? Evolutionary Ecology 24:1463-1474.
Dorken, M. E.& J. R. Pannell (2009) Sex allocation of hermaphrodites evolves in response to natural selection when mating opportunities change. Current Biology 19:514-517.
Dorken, M. E.&. E. T. A. Mitchard (2008) Phenotypic plasticity of hermaphrodite sex allocation promotes the evolution of separate sexes: an experimental test of the sex-differential plasticity hypothesis using Sagittaria latifolia (Alismataceae). Evolution 62:971-978.
Dorken, M. E., & J. R. Pannell (2009) Density-dependent regulation of the sex ratio in an annual plant. American Naturalist 171:824-830.
Information for prospective students:
I am always keen to discuss opportunities for graduate studies in my
lab. In addition to the projects listed below, I would welcome
students interested in studying a range of issues in plant evolution
and/or ecology.
1) Evolution of males: Most research on the evolution of separate
sexes has focussed on the evolution of females. This project involves
the use of genetic markers combined with experimental manipulations
of the mating environment to explore the conditions that promote the
evolution of males.
2) Evolution of trioecy: Trioecy refers to the stable maintenance of
three sexes in a population (females, males, and hermaphrodites). We
are trying to understand the conditions under which this breeding system is evolutionarily stable using a combination of field studies
in Spain and local experimental evolution studies of an annual plant.
3) Evolution of gynodioecy in an island radiation: Gynodioecy refers
to the co-occurrence of females and hermaphrodites. We are initiating
studies of a diverse plant lineage endemic to the Canary Islands to
understand the influence of the breeding system on patterns of
evolutionary diversification.
