We use the small soil nematode Caenorhabditis elegans as a model organism because of its relative cellular simplicity and suitability for genetic analysis. The complete cell lineage of the wild-type animal is known, and the nervous system has been completely reconstructed from serial section electron micrographs. The hundreds of genes affecting the many aspects of development and behavior that have been identified and mapped testify to the organism's advantages for genetic manipulation. C. elegans is also a model for genome sequencing, and at least a third of its genes have human homologs. One specific aim of our laboratory, in collaboration with the laboratory of Jocelyn Shaw, is to analyze developmentally important genes both functionally and molecularly.
Function is studied through the characterization of mutant phenotypes.
A variety of techniques, including germline transformation, are used to clone genes defined solely by mutant phenotypes. Genes affecting nervous system development, muscle function and signal transduction are currently under study. A second specific aim of of our laboratory is to identify the anatomical foci of action of developmentally important genes by analyzing genetic mosaics, animals in which different cells have different genotypes. The analysis of genetic mosaics has allowed us to draw conclusions about the primary anatomical foci of action of several genes known to affect behavior and development. For example, the actions of particular genes have been localized to particular sensory neurons, motor neurons, or body muscle cells.