Kimmel, Charles B.

We are interested in learning the nature of developmental mechanisms that produce patterned arrays of specific types of cells in vertebrate embryos. Along with several of our colleagues, we work with the zebrafish, a relatively simple vertebrate with desirable attributes for developmental and genetic analysis. A powerful way to address how early cells participate in forming the body tissues and organs is by directly following development of dye-labeled cell lineages in living embryos. We find that behaviors of embryonic cells are highly stereotyped. However, single-cell transplantation experiments shows us that cells are not irrevocably committed to their normal behaviors. Rather, what they do depends on interactions with their neighbors. We are using a mutational approach to characterize such interactions and to identify genes that control patterning. We screen for mutants with curious embryonic phenotypes, and we characterize these phenotypes in detail including mosaic analyses that show which embryonic cells the mutations directly affect. From such studies we formulate a genetic pathway of development of the early embryo. By cloning the mutant genes we will learn the underlying molecular basis of their actions.