Seminar Series 2005

Embryonic body patterning and segmentation of the amphipod crustacean, Parhyale hawaiensis

Melinda Modrell
Dept of Integrative Biology, UC Berkeley

A great deal is known about the genetic, molecular, and cellular mechanisms responsible for pattern formation in model systems, such as the fruit fly Drosophila melanogaster. The realization that many of the genes involved in setting up the Drosophila body plan are highly conserved not only among the arthropods, but also among other bilaterian phyla has led to remarkable insights about the evolution of development. Using the information available from Drosophila, we are investigating the level of conservation of the developmental pathways involved in pattern formation between various arthropods, in particular within the crustaceans.

To better understand the mechanisms of embryonic development and pattern formation within the crustaceans, we have established a “model” organism, the amphipod crustacean, Parhyale hawaiensis (Peracarida:Malacostraca:Crustacea) in which we can study development in great detail. Some of the major areas of research within the Patel lab include: establishment of cellular asymmetries, regulation of germ layer formation, the evolution of segmentation mechanisms, and the role of Hox genes in generating morphological diversity of segments and appendages. We have cloned a number of Parhyale orthologs of genes known to be involved in pattern formation in Drosophila, and we are examining their expression patterns to discern their roles during Parhyale development. By analyzing orthologs of genes in a variety of arthropods and examining their expression patterns during development, we may be able to understand how developmental programs have changed during evolution, and how molecular changes may provide insight into the diversification of developmental mechanisms and body morphologies.

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