Fig. 7. Endoderm is specified in Mixl1^–/– embryos. (A-D) Expression of Afp in 7.5 dpc wild-type (+/+) (A,B) and Mixl1^–/– (–/–) embryos (C,D). Lateral (A,C) and anterior views (B,D) showing Afp expression in the visceral endoderm of the vitelline yolk sac, but not in the definitive endoderm (de). The Afp expression domain seems to extend more distally in the mutant embryo. (E,F) Cer1 is expressed in anterior definitive endoderm of the late bud/early head fold stage Mixl1^–/– embryo (F) and of the early bud stage wild-type embryo (E). (G,H) Sox17 is expressed in the anterior definitive endoderm of the early-bud wild type and Mixl1^–/– embryo (arrows).