Fig. 2. Comparison of the oscillating pattern of deltaC expression with the non-oscillating expression of deltaD and notch1. (A) In wild-type embryos, notch1 is always expressed uniformly throughout the PSM, indicating that its expression does not oscillate. myoD expression is shown in red. (B-I) Wild-type embryos were staged and analyzed as previously described (Holley et al., 2000). (B-E) Representative early and late 12-somite stage embryos stained for deltaC (C) (B,C) or deltaD (D) (D,E) in blue and counterstained for myoD in red. In each panel, anterior is upwards. (F-I) Graphs depicting the distances that separate anterior of deltaC stripes 13 and 14 at the early (F) and late (G) 12 somite stage. The distances separating deltaD stripes 13 and 14 at the early and late 12 somite stages are depicted in H and I, respectively. Note that in H, no data points exist because the more posterior deltaD stripe has not formed yet. Measurements were made in pixels and later converted to number of cells (8 pixels/cell). Mean values are represented by broken lines. The mean values for F and G were compared using a two-sample t-test. The difference between the means in F and G is 25.25 pixels (3.1 cells) with a 95% C.I. from 18.7 to 31.7 pixels indicating that the differences between the data in F and G are significant. This indicates that, as for her1, the distance between consecutive deltaC stripes decreases as the somite cycle progresses.