The boundaries of relative levels of ftz expression. Plotted are the averaged locations of various threshold levels of ftz expression derived from 155 embryos, computed and displayed similarly as in Figure 6. For example, those cells expressing ftz above 75% of the maximum level of expression are shown in red. Note the shape of the stripes above the 50% threshold is similar to that given by the inflection points (Figure 6), but not equal. For example, the dorsal-most point of stripe 7 is less than 50% of the maximum expression level for more than half the embryos (that is, the stripe at that point is not shown in this graph). Egg length (EL).