Scroll to Section:

Plants, animals, and fungi show a huge diversity regarding form and phenotype: the observable characteristics of an organism. The research presented in this video uses the model of a particular roundworm to investigate how the phenotype is changed by the environment; this is known as phenotypic plasticity. RALF SOMMER explains that Pristionchus pacificus develops alternative mouth forms depending on their environment, either feeding on bacteria or on other roundworms. By manipulating the worms’ genome, the researchers identified one gene which, if deactivated, results in animals that no longer develop the predatory mouth form. Theoretical biologists have been suggesting the existence of so-called developmental switch genes that determine which of several traits encoded in the genome of an individual is formed. Such genes had, however, not yet been identified. Further experiments revealed that this developmental switch is not constituted by one single gene but is part of a more complex genetic network.


Ralf Sommer is Director at the Max Planck Institute for Developmental Biology in Tübingen, where he previously worked as a Young Investigator. He is also Honorary Professor at the University of Tübingen, Germany. His research in the field of evolutionary biology combines laboratory studies with fieldwork to investigate how developmental phenotypic plasticity influences biological diversity.
Sommer is a recipient of the Falcon Prize of the German Society for Cell Biology and an elected member of the European Molecular Biology Organization (EMBO).


Max Planck Institute for Biology Tübingen

Basic research at the Max Planck Institute for Biology Tübingen addresses fundamental questions in microbial, algal, plant and animal biology, including the interaction between different organisms. The approaches we use range from biochemistry, cell and developmental biology to evolutionary and ecological genetics, functional genomics and bioinformatics. The institute currently has five active departments, each led by a Director

Show more

Original publication

The Nuclear Hormone Receptor NHR-40 Acts Downstream of the Sulfatase EUD-1 as Part of a Developmental Plasticity Switch in Pristionchus

Rödelsperger Christian, Sommer Ralf J., Kieninger Manuela R., Ivers Nicholas A., Markov Gabriel V. and Ragsdale Erik J.
Current Biology
Published in 2016

Chromatin Remodelling and Antisense-mediated Up-regulation of the Developmental Switch Gene eud-1 Control Predatory Feeding Plasticity

Serobyan Vahan, Xiao Hua, Namdeo Suryesh, Rödelsperger Christian, Sieriebriennikov Bogdan, Witte Hanh, Röseler Waltraud and Sommer Ralf J.
Nature Communications
Published in 2016

A Developmental Switch Coupled to the Evolution of Plasticity Acts through a Sulfatase

Rödelsperger Christian, Sommer Ralf J., Ragsdale Erik J. and Müller Manuela R.
Published in 2013

Reading recommendations

Antagonism of LIN-17/Frizzled and LIN-18/Ryk in Nematode Vulva Induction Reveals Rvolutionary Alterations in Core Developmental Pathways

Sommer Ralf J. and Wang Xiaoyue
PLoS Biol
Published in 2011

Co-option of the Hormone-signalling Module Dafachronic Acid-DAF-12 in Nematode Evolution

Sommer Ralf J., Bento Gilberto and Ogawa Akira
Published in 2010

The Pristionchus Pacificus Genome Provides a Unique Perspective on Nematode Lifestyle and Parasitism

others, Dieterich Christoph, Clifton Sandra W., Schuster Lisa N., Chinwalla Asif, Delehaunty Kimberly, Dinkelacker Iris, Fulton Lucinda, Fulton Robert, Godfrey Jennifer and Minx Pat
Nature Genetics
Published in 2008

Conservation and Diversification of Wnt Signaling Function During the Evolution of Nematode Vulva Development

Sommer Ralf J., Zheng Min, Messerschmidt Daniel and Jungblut Benno
Nature Genetics
Published in 2005

The Homeotic Gene Lin-39 and the Evolution of Nematode Epidermal Cell Fates

Sommer Ralf J. and Eizinger Andreas
Published in 1997
Show more