During the morphogenetic movements of gastrulation, cells that will form internal tissues become positioned within the interior of the developing embryo.   We use the nematode C. elegans as a model to understand some of the basic cellular events that occur during gastrulation.   C. elegans gastrulation involves the ingression of cells into a small blastocoel cavity in the interior of the embryo.   We are interested in understanding 1) how the blastocoel cavity forms, 2) how ingression movement occur, 3) how ingressions are triggered and patterned, and 4) how early embryonic cells acquire an apicobasal polarity that is important for blastocoel formation and ingression.   C. elegans is ideally suited for such studies, since individual cell movements can be followed in the optically clear embryo and genes involved in gastrulation can be identified using genetics.