The <i>hes6</i> mutant phenotype is epistatic to the <i>her7</i> mutant phenotype.

<p>(A) Wildtype (wt, upper left), <i>her7</i> mutant (upper right), <i>hes6</i> mutant (lower left), and <i>her7;hes6</i> double mutant embryos (lower right) at 34 hpf stained for <i>cb1045</i> expression to analyze segmentation. Posterior segmentation defects (red arrowheads) are fully penetrant in <i>her7</i> mutants, but not in <i>hes6</i> mutant and <i>her7;hes6</i> double mutant embryos. Numbers indicate number of embryos with and without segmentation defects for <i>hes6</i> and <i>her7;hes6</i> mutants. Whole mount preparations, anterior to the left, scale bar 300 µm. (B) wt (upper left), <i>her7</i> mutant (upper right), <i>hes6</i> mutant (lower left), and <i>her7;hes6</i> double mutant embryos (lower right) at the 10-somite stage in situ stained for <i>her7</i> expression (blue). Formed segments are labeled by staining for <i>myoD</i> mRNA expression (brown). Two representative examples with different expression patterns are shown for wt, <i>hes6</i>, and <i>her7;hes6</i> mutants to indicate evidence for ongoing tissue-level oscillations. Patterns in all <i>her7</i> mutants examined were similar, and one representative example is shown. Flat mount preparations, anterior to the top, scale bar 50 µm.