The Caenorhabditis elegans embryo has anterior/posterior, dorsal/ventral, and left/right axes that correspond to spatially asymmetric patterns of cell differentiation. Recent studies have provided insight into how the different embryonic axes are determined and have shown that the products of the
glp-1,
skn-1,
cap-1, and
cap-2 genes appear to be distributed asymmetrically in the early embryo. These gene products should provide important tools for understanding how asymmetries are established initially in nematode embryogenesis.