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People >> Prof. Thorsten Reusch

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Thorsten Reusch
Head of group
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Research interest

Evolutionary Ecology in a changing world

The focus of my research is the ecology of evolution. Any ecological interaction is also a selection pressure. Consequently, if there is heritable variation, evolutionary change will take place. There is now ample evidence that the separation between ecological and evolutionary scale is misleading. Both time scales are commensurate and should be answered within a common framework.
Given the predicted environmental changes in the next decades, one focus area of our group will be the evolutionary response of populations to global change. Towards this end, both heritable variation within populations, and the distribution of genetic variation across latitudinal gradients needs to be quantified. Such an approach will benefit from an expansion of the evolutionary ecology toolbox. For example, transcription profiling, genome scans and QTL mapping all aim at defining the genetic basis for ecologically important traits. Once selectively relevant polymorphism is identified, predictions on the evolutionary potential of populations become possible.

Rapid adaptation in the face of global change - Contemporary climate change is characterized both by increasing mean temperature and increasing climate variability such as heat waves, storms and floods. How populations and communities cope with such climatic extremes is a question central to contemporary ecology and biodiversity conservation. Our previous work with marine macrophytes (eelgrass, Zostera marina) has shown that genotypic diversity can replace the role of species diversity in a species-poor coastal ecosystem, and may buffer against extreme climatic events (PNAS vol. 102, pp. 2826-2831). Net biodiversity effects were explained by genotypic complementarity rather than selection of particularly robust genotypes.

At present we lack a synthetic understanding when, how and why rapid adaptive evolution takes place in one system but not another. As a first step, in order to gain an overview, our lab is assembling a data base on rates of contemporary evolution across as many diverse systems, selection pressures and traits as possible. Interestingly, fish species including salmonids and sticklebacks, provide many excellent examples for rapid adaptive in the face of invasions, exploitation, or global change. Whether this is due to some particular genetic /genomic feature of bony fishes, for example their whole genome duplication, or due to observer bias is unknown.

Advancing the toolbox: application of genomics and transcriptomics in non-model organisms - In collaboration with the Max-Planck Institute of Molecular Genetics in Berlin (group Richard Reinhard), and we are currently developing genomic resources for ecologically important species such as the marine angiosperm Zostera marina and three-spined sticklebacks.

In three-spined sticklebacks (Gasterosteus aculeatus), the genome and high-density linkage maps are already available (stickleback genome), while high-quality EST data are yet to be developed. One goal is to produce an exhaustive microarray that contains all immunologically relevant genes in order to assess gene expression as a function of habitat type, infection status, and reproductive traits (collaboration with Prof. Manfred Milinski, Max-Planck-Institute for Evolutionary Biology Plön). Genome sacns that aim at detecting positive selection are underway for immunologically relevant genes of the innate response (Msc project of Anja Westram).

In the marine flowering plant eelgrass (Zostera marina) we are not yet so far. Our goal is to make this ecosystem engineering species a marine plant model in ecological genomics. Towards this end, expressed sequence tag libraries are currently being annotated and compared among different environmental conditions, in collaboration with the Evolutionary Bioinformatics group (Erich Bornberg-Bauer, Amelie Veron, Januar Weiner, Lothar Wissler: Evolutionary Bioinformatics, see Zostera databasee). The development of expression systems using quantitative PCR of selected stress genes is in progress. Based on these EST resources, we are also developing EST-linked microsatellite markers and SNP typing systems (together with the MARBEE group, University of Groningen (Profs. Jeanine Olsen, Wytze Stam,) for genome scan approaches towards identifying signals of divergent selection among contrasting habitats (PhD projects of Katharina Oetjen and of Steven Ferber). This project is funded by DFG (RE 1108/7).

Selected Publications

Wegner KM, Kalbe M, Reusch TBH (2007) Innate versus adaptive immunity in sticklebacks: evidence for trade-offs from a selection experiment. Evolutionary Ecology, 21, 473-483.

Reusch TBH, Wood TE (2007) Molecular Ecology of global change. Molecular Ecology, 16, 3973-3992.

Reusch TBH (2006) Does disturbance enhance genotypic diversity in clonal organisms? - a field test in the marine angiosperm Zostera marina. Molecular Ecology, 15, 277-286.

Rauch G, Kalbe M, Reusch TBH (2006) One day is enough: rapid and specific host-parasite interactions in a stickleback-trematode system. Biology Letters, 2, 382-384.

Reusch TBH, Langefors ┼ (2005) Inter- and intralocus recombination drive MHC class IIB gene diversification in a teleost, the three-spined stickleback Gasterosteus aculeatus. Journal of Molecular Evolution, 61, 531-541.

Reusch TBH, Ehlers A, Hämmerli A, Worm B (2005) Ecosystem recovery after climatic extremes enhanced by genotypic diversity. Proceedings of the National Academy of Sciences USA, 102, 2826-2831.

Reusch TBH, Häberli MA, Aeschlimann PB, Milinski M (2001) Female sticklebacks count alleles in a strategy of sexual selection explaining MHC polymorphism. Nature, 414, 300-302.

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