Fig. 7.

Quantification of PCD in the E11.5 foregut. Box plots showing PCD indices from E11.5 saline-treated CBA/Ca mice at different rostro-caudal levels. Dorso-ventral zones are defined as in Fig. 6. Arrows indicate level at which foregut separation has occurred at this stage. (A) PCD data for dorso-ventral zones with additional data (brown and pink boxes) for the middle and lateral tracheal segments to illustrate budding of the bronchi. (B) PCD data for dorsal-most and middle segments at levels 2 to 5. Note ventral-to-dorsal switch in predominance of PCD as separation proceeds from caudal to rostral within the foregut (compare black and grey bars in A). The point of foregut separation coincides with a peak of PCD (A), with middle dorso-ventral zone showing greatest intensity of apoptosis (B).