Ralf Sommer

Integrative Evolutionary Biology

Max Planck Insitute for Biology
Faculty in: TIPP, IMPRS


  • Diplom in Biology 1989, RWTH Aachen & University of Tübingen
  • PhD work 1989-92 at the Ludwig-Maximilians University Munich
  • Research fellow 1993-95 at CALTECH, Pasadena, USA
  • Director at the MPI since 1999
  • Adjunct Professor, University of Tübingen since 2002

Research Interest
My primary scientific interest is to unravel the mechanisms that give rise to evolutionary alterations and novelty. We use an interdisciplinary approach that integrates development, ecology and population genetics. We study the nematode Pristionchus pacificus, which we have established as a model system. P. pacificus combines laboratory studies building on forward genetic, CRISPR-engineering, genomic and transgenic tools with field work. A core aspect of our current research is developmental plasticity, a concept that has recently received a lot of attention as a facilitator of phenotypic diversity.






Available PhD Projects

  • Transgenerational inheritance in P. pacificus: The Department of Integrative Evolutionary Biology has an active research program studying the predatory model nematode Pristionchus pacificus with state-of-the-art facilities in molecular biology, biochemistry, nematode genetics, CRISPR-engineering, genomics, and bioinformatics. Our highly interdisciplinary research team works at the interphase between development, evolution and ecology. We investigate among others, the development and evolution of mouth-form plasticity with two alternative, predatory or bacterial feeding morphs. We have recently discovered long-lasting transgenerational inheritance and epigenetics of diet-induced plasticity. A genetic screen for transgenerational inheritance-defective mutants identified a set of epigenetic factors and allows unprecedented studies of the associated molecular and biochemical mechanisms. We are now looking for a PhD student to join the department and study transgenerational inheritance in P. pacificus.

    Applications are now closed.

Selected Reading

  • Lightfoot, J. W., Wilecki, M., Roedelsperger, C., Moreno, E., Susoy, V., Witte, H. & Sommer, R.J. (2019): Small peptide mediated nematode self-recognition prevents cannibalism. Science, 364, 86-89, doi: 10.1126/science.aav9856.
  • Lightfoot, J. W., Dardiry, M., Kalirad, A., Giaimo, S., Eberhardt, G., Witte, H., Wilecki, M., Roedelsperger, C., Traulsen, A., & R. J. Sommer, R.J. (2021):  Sex or cannibalism: polyphenism and kin recognition control social action strategies in nematodes. Science Advances, 7, eabg8042.
  • Sieriebriennikov, B., Prabh, N., Dardiry, M., Witte, H., Rödelsperger, C., Röseler, et al. (2018): A developmental switch regulating phenotypic plasticity is a part of a conserved multi-gene locus. Cell Report, 23, 2835-2843, doi: 10.1016/j.celrep.2018.05.008
  • Ragsdale, E., Müller, M., Roedelsperger, C. & Sommer, R. J. (2013): A developmental switch coupled to the evolution of plasticity acts through a sulfatase. Cell 155, 922-933, doi: https://doi.org/10.1016/j.cell.2013.09.054
  • Sieriebriennikov, B., Sun, S., Lightfoot, J.W., Witte, H., Moreno, E., Rödelsperger, C., & Sommer, R.J. (2020): Conserved hormone-receptors controlling a novel plastic trait target fast-evolving genes expressed in a single cell. PLoS Genetics, 16, e1008687.
  • Bento, G., Ogawa, A. & Sommer, R. J. (2010): Co-option of the hormone-signalling module dafachronic acid–DAF-12 in nematode evolution. Nature 466, 494-497, doi: 10.1038/nature09164
  • Renahan, T., Lo, W.-S., Werner, M. S., Herrmann, M., Rochat, J. & R. J. Sommer (2021): Nematode biphasic ‘boom and bust’ dynamics are dependent on host bacterial load while linking dauer and mouth-form polyphenisms. Environmental Microbiology, 23, 5102-5113, doi: 10.1111/1462-2920.15438
  • Renahan, T. & R. J. Sommer (2021): Nematode interactions on beetle hosts indicate a role of mouth-form plasticity in resource competition. Frontiers in Ecology and Evolution, 9:752695.


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