Evolution of arthropod segmentation
Bodies built from repeated segments are found in three major taxa. Commonly, these animals develop segments sequentially, in an anterior-to-posterior progression. Vertebrates and, more recently, arthropods, have been shown to use a “clock”-like mechanism to sequentially pattern their segments. The segmentation clock in the flour beetle, Tribolium castaneum, uses a “bare bones” oscillator created by a three-gene network comprised of mutually interacting transcription factors. Our current project uses an interdisciplinary approach aimed at understanding this novel segmental oscillator.
Creating fate and ablation maps to understand how gene networks pattern development.
Tribolium is arguably second only to Drosophila as the best-studied insect developmental system. Surprisingly, the experiments that serve as the foundation for understanding development in any species remain incomplete in Tribolium. In particular, detailed fate maps and ablation maps of the blastoderm and early germband embryos are only recently being reported. Cell lineage and fate map analysis provide the foundation for understanding development in any system and have been extensively used in all model systems. We recently completed a preliminary fate map of the Tribolium blastoderm, and we are continuing those investigations.
Investigating the regulation of segment number in arthropods.
As one of the most morphologically diverse group of bilaterians, arthropods generate much of their morphological diversity through variation in their axial body plan, mainly via segment number and identity. Segment number alone is a significant, but underappreciated, component of arthropod morphological diversity among its subphyla. For example, segment number ranges from 9 to 192. This diversity is predominantly attributed to differences in the number of segments in the posterior body region (i.e. abdomen, trunk, or opisthosoma), as the total number of segments in the anterior body region (i.e. head, thorax, or prosoma) is generally invariable within each subphylum. In a project initiated by former graduate student Ryan Pace, we are using molecular genetics to probe the regulation of segment number in arthropods.
Using computational models to connect the read-out of the segmentation clock to a field of growing cells.
During our previous funding, through the hard work of postdoc Susan Hester, we published a CompuCell3D model of Tribolium segmentation. A revised model simulates the formation of all trunk segments by imposing forces that reproduce cell movements observed in the early embryo. We are using the revised model as a platform for exploring questions about the gene network that patterns segmentation.
Collaborative Lab Projects:
Segmentation in the branchipod crustaceans Thamnocephalus
Other Lab Projects:
The lab has also been home to a diverse range of other projects. Essential to Understanding phenotypic diversity is the exploration of a broad range of species. I have encouraged graduate students and postdocs to develop novel organismal systems. This comes with its challenges, but is always exciting…below are a few examples of projects that lab members have worked on….
- PhD students Triops and Artemia
- PhD students Dave Lambert, Jessie Wandelt, James Cooley and postdoc Ayaki Nakamoto
- PhD students Bob
- PhD students
- Postdoctoral fellow