averof lab

Development and Evolution

 

research interests

Axis elongation and segmentation: The majority of arthropods generate their segments sequentially from a posteriorly located growth zone, a process known as 'short-germ' development. Parallels to this can be found in vertebrates, where somites are generated sequentially from a posteriorly located pre-somitic zone. The mechanisms underlying this process are poorly understood. We are developing genetics and imaging approaches to study this process in the beetle Tribolium castaneum.


Hox genes and the evolution of segment specialization: All arthropods share the same set of Hox genes, although their bodies show strikingly diverse patterns of segment specialization. These differences involve changes in the expression patterns of Hox genes and in the regulation of Hox downstream targets. We are developing genetic tools to explore these changes, mis-expressing Hox genes and studying their target cis-regulatory elements across species.


Origin of key evolutionary novelties: Our work suggests that insect wings and respiratory organs (tracheae) evolved from limb branches that probably functioned as gills in the aquatic ancestors of insects. The spiders' book lungs, tracheae and spinnerets appear to have evolved independently from related structures. We are investigating the origin of tracheae in other groups of terrestrial arthropods, and looking for key molecular-developmental changes that were associated with the evolution of these structures.


Origin and plasticity of cells during regeneration: During regeneration, body parts that have been injured or amputated are rebuilt from progenitor cells that reside in the amputated stump. In most animals the identity, developmental potential and plasticity of these progenitor cells are unknown. We use genetic lineage-tracing and live imaging techniques to address this question in regenerating crustacean (Parhyale) limbs.


Structure, function and evolution of the visual system: The visual systems of arthropods participate in a variety of tasks including habitat selection, mate choice, prey capture and navigation. The structure, optical properties and neural connectivity of their eyes vary according to the tasks they perform in each species. We use genetic tools to investigate the structure and function of the visual system in the small crustacean Parhyale.


Transgenesis and gene targeting in emerging models: We are establishing genetic techniques that allow us to study development and gene function in two emerging model organisms, the beetle Tribolium castaneum and the crustacean Parhyale hawaiensis. Our efforts focus on techniques for gene editing (CRISPR), gene trapping, conditional gene expression, clonal analysis and live imaging.