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Integrative evolutionary biology

Ralf Sommer

Ralf Sommer

  • 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

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 genetic, genomic and transgenic tools with field work. One of our core activities is in evo-devo: studies on vulva development indicate that C. elegans and P. pacificus form their egg-laying structure from the same precursor cells, but use distinct signaling pathways. An unusual Wnt pathway with novel protein domains induces the vulva in P. pacificus and represents an example of developmental systems drift.

In our integrative approach we try to link evo-devo with population genetics and ecology. P. pacificus lives on scarab beetles and we currently explore genetic, genomic and neurobiological aspects of ecologically relevant traits, such as the evolution of predatory feeding. More than 400 strains of P. pacificus from around the world provide material for natural variation and population genetic studies. We established a field station on La Réunion in the Indian Ocean, where P. pacificus is associated with different beetles allowing integrative studies in a microcosmic setting.

Selected Reading

1) Bumbarger DJ, Riebesell M, Rödelsperger C, Sommer, RJ (2013): System-wide rewiring underlies behavioral differences in predatory and bacterial-feeding nematodes. Cell, 152, 109-119.

2) Wang X,  Sommer, RJ (2011): Antagonism of LIN-17/Frizzled and LIN-18/Ryk in nematode vulva induction reveals evolutionary alterations in core developmental pathways. PLoS Biology, 9, e1001110.

3) Bento G, Ogawa A, Sommer, RJ (2010): Co-option of the hormone-signalling module dafachronic acid–DAF-12 in nematode evolution. Nature, 466, 494-497.
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Scanning electron micrograph of Pristionchus pacificus. 

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Predatory feeding of P. pacificus on another nematode.