Fig. 4.

Periodicity of Tc-eve oscillation in the blastoderm and germband. (A) The duration of each class of Tc-eve expression (estimated from Fig. 2, bottom row) is represented by the width of the black boxes. This is equivalent to combining all egg collections into one large collection, spanning 12-24 hours after egg laying, then using the overall percentage of embryos in each class as an estimate of its duration (percentages rather than absolute numbers are used in calculations to correct for differences in the number of eggs in each collection). Tc-eve expression at the posterior end of the blastoderm is shown above the black boxes (red bars, high Tc-eve; blue bars, low Tc-eve; question mark indicates uncertainty due to primitive pit formation). (B) The estimated duration of Tc-eve cycles for blastoderm (taken from A) and germband (determined from supplementary material Fig. S3, for stripes 4, 5 and 6) are represented by the width of the black boxes.