Effect of Rubie ablation on heart development at E15.5. (A-C,E) Oblique transverse Hematoxylin and Eosin histological sections of cardiac ventricular and OFT morphogenesis at E15.5. (A) Representative wild-type morphology. (B) Representative Rubie−/− morphology. (C) Representative Bmp4+/− (Actb-Cre+) morphology. (D) Left: electrophoresed gDNA PCR genotyping products of Rubie and Actb-Cre transgene alleles. Right: offspring recovered at weaning from Rubie+/−; Actb-Cre+×Bmp4fl/fl mating versus expected Mendelian ratios. (E) Representative Bmp4+/−; Rubie+/− (Actb-Cre+) morphology in two separate individuals. RV, right ventricle; LV, left ventricle; OFT, outflow tract; WT, wild type. Scale bars: 300 µm. Arrows indicate distorted OFT orientation. P-values were obtained using a χ2 test.