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Abteilung 4 Evolutionsbiologie
Direktor:
Dr. Ralf J. Sommer
Administrative Assistant: Kostadinka Krause
Tel.: +49 (0)7071 - 601 441
Fax: +49 (0)7071 - 601 498
Mitarbeiter: Alphabetische
Liste
Alumni
Mission Statement and Introduction
Integrative Evolutionary Biology
Life
on Earth resulted in an astonishing diversity of form and phenotype.
But our understanding on how this diversity is generated as a result of
historical processes is still limited. We use a highly interdisciplinary
approach that integrates development, ecology and population genetics
to unravel the mechanistic changes that give rise to evolutionary
alterations and novelty (Sommer, 2009). For this to be achieved
well-selected model organisms with a sophisticated toolkit for
functional investigations have to be developed. We have established the
nematode Pristionchus pacificus as a model system in evolutionary
biology. P. pacificus combines laboratory studies building on genetic,
genomic and transgenic tools with field work in ecology and population
genetics.
One of our core activities is in evolutionary
developmental biology (evo-devo). By investigating the evolution of
developmental processes, we aim for a mechanistic understanding of
phenotypic change. Our studies on vulva development show that
Caenorhabditis elegans and P. pacificus form their egg-laying structure
from the same precursor cells, but use distinct molecular mechanisms. An
unusual Wnt pathway regulates vulva development in P. pacificus
representing an example of developmental systems drift (Wang &
Sommer, 2011). This diversity is also reflected at the level of the
genome with massive expansions in gene number and a strong influence of
novel genes, in part acquired by horizontal gene transfer (Dieterich et
al., 2008; Rödelsperger & Sommer, 2011).
Our
interdisciplinary research program tries to integrate evo-devo with
population genetics and ecology to i) indicate the contribution of
natural variation to the evolution of development and ii) reveal how
developmental processes evolve under changing environmental conditions.
Since 2004, we could show that P. pacificus and related worms live on
scarab beetles in a necromenic association. Worms rest on the living
beetle in the dauer stage and only start feeding on microbes after the
beetles´ death. These findings have opened many new research avenues
that are currently explored to investigate the developmental basis of
ecologically relevant traits (Bento et al., 2010).
Our third goal
is to provide integration of evo-devo with population genetics. More
than 400 P. pacificus strains and nearly 30 Pristionchus species have
been isolated, providing material for studies of natural variation. In
2010, we have opened a field station on La Réunion in the Indian Ocean,
an island on which P. pacificus is associated with several different
scarab beetles and that harbors the complete worldwide genetic diversity
of P. pacificus (Herrmann et al., 2010; Morgan et al., 2012). We use
the La Réunion microcosm for the population level analysis of ecological
and developmental traits by performing genome wide association studies
and QTL analysis. In this tripartite system – evo-devo, ecology and
island population genetics - we link micro – and macroevolutionary
investigations to provide a comprehensive and integrative view of
evolution (Sommer, 2009).
To this end the Pristionchus research in the Department focuses on four different areas:
1) The evolutionary analysis of developmental processes (evo-devo),
2) The genetic analysis of species interactions and the ecology of Pristionchus nematodes (evolutionary ecology),
3) Population genetics of P.pacificus in the context of La Réunion Island in the Indian Ocean,4) Resource and Methods development.
Introductory References:
Sommer, R. J. & Ogawa, A. (2011): Hormone signaling and phenotypic plasticity in nematode development and evolution. Curr. Biol., 21, R758-R766.
Sommer, R. J. (2009): The future of
evo-devo: model systems and evolutionary theory. Nature Rev.
Genetics, 10, 416-422.
Dieterich, C. & Sommer R. J. (2009):
How to become a parasite – lessons from the genomes of nematodes.
Trends in Genetics, 25,
203-209.
Dieterich, C., Clifton, S.W., Schuster, L.N., Chinwalla, A.,
Delehaunty, K., Dinkelacker, I.,
Fulton, L., Fulton, R., Godfrey, J., Minx, P., Mitreva, M., Roeseler,
W., Tian, H.,
Witte, H., Yang, S.P., Wilson, R.K., Sommer, R.J. (2008): The
Pristionchus pacificus genome provides a unique
perspective on nematode lifestyle and parasitism. Nature
Genetics, 40, 1193-1198.
Sommer, R. J. (2008):
Homology and the hierarchy of biological systems.
BioEssays, 30, 653-658.
Hong, R. L. and Sommer, R. J. (2006): Pristionchus pacificus – a well rounded nematode. BioEssays, 28, 651-659.
Departmental Publication list
Research
Projects
Vulva development in Pristionchus pacificus
Pristionchus
pacificus Genomics and Proteomics
Microevolution of vulva development in Pristionchus pacificus
The evolution of dauer formation
Pristionchus – biology and taxonomy
Evolutionary field station on Reunion island
Pristionchus - Population Genetics and Ecology
Comparative Connectomics: Whole animal dense neural circuit reconstruction
Developmental plasticity: A facilitator of novelty
Microbial
Interactions – pathogenicity
Associated Research
Groups
Nematode
development (Adrian Streit)
Links
The Genome Sequencing Center Washington St Louis