Fig. 6. Functional classification of Hox downstream genes using GO categories. (A) Functional categories of downstream genes are shown for all newly identified Hox downstream genes (first column), for all identified Dfd downstream genes (second column), for all predicted direct Dfd target genes (third column) and for all known direct Hox target genes (fourth column). Numbers of genes for each category are indicated within bars. (B) Diagram showing subclasses of realizator genes, with numbers of genes for each class indicated. (C) Subclasses of realizators are often coordinately regulated, as shown here by three examples (apoptosis, cell adhesion, cell cycle or cell proliferation). Green arrows, increased expression; red arrows, reduced expression. (D) Morphological differences along the AP axis are reflected in the percentage of shared downstream genes regulated opposingly by two different Hox proteins. Light gray indicates similar morphologies; medium gray and dark gray indicate increasing differences in morphologies directed by the Hox genes compared. The scanning electron micrograph shows the morphology of a stage 13 embryo, with the expression domains of the different Hox proteins highlighted.