different-colored antibody stains, we can see exactly where and to what degree Hox genes are expressed. This is a photograph of a fly embryo,
once again with its anterior end to the left. It shows the expression pattern
of four different Hox genes—Scr (black), Antp
(red), Ubx (blue), and Abd-B (brown). As you can see, each Hox gene is expressed in a specific region along the
anterior-to-posterior axis of the embryo. Now have a look at what results from
such expression in the mature animal.