Registration of mutant mice across all three mouse lines reveals that <i>Dll4</i> have significantly different signal intensity maps compared to <i>Mlc2a</i> and <i>Eng</i> mice.

<p><i>Dll4</i>^-/- mice were compared to the pooled population of <i>Mlc2a</i>^-/- and <i>Eng</i>^-/- mice at all time points after registration. (A-C) are sagittal slices through an individual <i>Eng</i>-/-, <i>Mlc2a</i>^-/-, and <i>Dll4</i>^-/- mouse, respectively. The red cross-hair corresponds to the common ventricle in both the <i>Eng</i>^-/- (A) and <i>Mlc2a</i>^-/- (B) mouse, but not in the <i>Dll4</i>^-/- mouse (C) because its heart tube is still linear. (D) illustrates this statistically: the average autofluorescence map has been overlaid with the signal intensity map, and the <i>Dll4</i>^-/- mice display a lack of signal intensity (blue shading) in the area where the common ventricle should be forming. Slices through the vascular scan of each embryo confirms this finding (A′—D′). The red cross-hair is placed in the centre of the antrioventricular canal of the <i>Eng</i>^-/- mouse (A′), the <i>Mlc2a</i>^-/- mouse (B′), but not in the <i>Dll4</i>^-/- mouse (C′). Statistically, this is illustrated when the average vascular scan is overlaid with the signal intensity map (D′): the <i>Dll4</i>^-/- mice display a lack of signal (blue shading) in the outer ventricle area of the heart compared to the pooled <i>Eng</i>^-/- and <i>Mlc2a</i>^-/- embryos. The colour bar presents the t-statistic of which the minimum corresponds to a FDR threshold of 10%. Scale bar = 500μm.