C. elegans is a free-living nematode that normally inhabits the soil. It is non-pathogenic. The cell lineage is largely invariant and transparency of the worms reveals each nucleus in the body when viewed in the microscope at high power. This feature has allowed the entire lineage to be traced. Genetic manipulations are well developed (both "forward" and "reverse"). The genome is fully sequenced.

Faculty working on worms: J. Nance, D. Fitch, J. Hubbard, F. Piano

Drosophila is commonly known as the fruit fly. It has been used as a model system in biology since being established in the laboratory of Thomas H. Morgan in 1909. Its tremendous history provides an extensive database of genes and mutants that has now been extended by the complete genome sequence. Powerful forward genetics coupled with the ability to make transgenic flies through transposable elements provide a model system that have facilitated our understanding of everything from body patterning to organ development to neurogenesis.

Faculty working on flies: E. Bach , J. Dasen , R. Dasgupta , C. Desplan , R. Lehmann, C. Rushlow, H.D. Ryoo , M. Siegal , S. Small, G. Suh , J. Treisman