Fig 3. Notch1R1974A substitution compromised ventricular septum development.
A. Normal heart with complete septum. B. N1RA/–; N2RA/–heart with a severe, highly penetrant VSD. The penetrance by age shown below the image. C. N1RA/–; N2+/RA heart with a milder, less penetrant VSD. E, embryonic day; N1RA/–; N2+/RA, Notch1 Arg1974Ala Notch2 Arg1934Ala hemizygous; VSD, ventricular septal defect.