Development and Evolution of Bilateria

Acoel flatworms attract researchers attention as representatives of the Acoelomorpha which are positioned by molecular systematics as the sister group of the remaining Bilateria. Studies of the development of this organism allows to 1. reconstruct the ancestral function of developmental genes in the common protostome-deuterostome ancestor and 2. give insights to the evolution of important characters of the bilaterian animals like mesoderm and nervous system evolution. 3. Allows insights into the origin of stem cell and immune systems

With degenerate primers I amplify genes which play an important role in most proto- and deuterostome animals and investigate their expression pattern during the development of the acoel Convolutriloba longifissura. I focus in my studies on genes for body axis specification and the specification of the mesodermal layer. The last common ancestor of the Acoelomorpha and the remaining Bilateria (Nephrozoa) was the first, which had a bilateral symmetric body and mesoderm. Furthermore, this stem species was the first showing an orthogonal nervous system with a brain like concentration at the anterior pole. I generated expression patterns of essential genes for anterio-posterior and dorso-ventral patterning, genes patterning the nervous system and genes determinating the characteristics of the mesodermal layer of a series of developmental stages. Bringing all these genes together it generates a picture of the ancestral constitution of the bilaterian ancestor that lived over 550 myr years ago and lets us fine-tune current scenarios of bilaterian evolution.

Right now I am working on the establishment of experimental procedures to study the cell biology of sensory cells, symbiont host interactions and immune responses. The insights from acoel flatworms will yield to an better understanding of the cell biology of these cells in other animals including humans. A large scale EST-Project to describe the developmental transcriptome and the sequencing of the genome is in progress, and will facilitate the descriptve and experimental approach.

My other projects connected to the AToL NSF project for Protostomes:

  • Describing Developmental Diversity: cell lineage studies with 4D-microscopy and cell lineage tracers
  • Reconstructing Phylogenetic Relationships of the Metazoa: Phylogenomics and Morphology are the used tools to achieve this goal.

Convoluta symbiont

Convolutriloba longifissura has algal symbionts in its epithelium and two frontal eyes

Check out the article about Hawaiian worms in the National Geographic Magazine (Feb 2007), with Convolutriloba longifissura:

Hawaii´s Unearthy Worms - National Geographic Magazine

current projects

postdoc research