Hierarchical clustering of controlled vocabulary annotations. Columns of the matrix represent the 99 annotation terms from the controlled vocabulary that correspond to differentiated organs. Rows of the matrix represent 1,257 genes that are expressed in at least one of those embryonic structures. A black matrix cell indicates that a gene is expressed in the given structure. Both rows and columns are clustered using a binary distance metric and hierarchical complete linkage clustering. Green shading highlights clusters of embryonic structures that are part of the nervous system, cyan shading highlights clusters formed by components of the muscle system. Genes expressed specifically in the embryonic fat body are highlighted by a red rectangle, two separate clusters of genes expressed in the tracheal system are surrounded by blue and magenta rectangles. A cluster of genes expressed in the peripheral nervous system and not in the central nervous system is enclosed by the yellow rectangle.