Fig. 3. Fate map of embryos at stages 7 and 8. (A,D) A composite template of embryos with all injections at ‘0’ hours, represented by a colored circle (yellow, sinus venosus; blue, ventricle; red, atria; black, bulbus cordis or vitelline artery; and white, those that did not enter the heart) and number for each embryo at stages 7 (A) and 8 (D). The HFR at stage 7 (black rectangle, see Materials and Methods) was superimposed on a stage 7 embryo stained for Bmp2 expression (B) and Nkx2.5 expression (C). (E) The HFR at stage 8 is represented (on only one side) as a red domain on a stage 8 embryo stained for expression of Nkx2.5 mRNA. B,C reproduced, with permission, from Ehrman and Yutzey, 1999. E reproduced, with permission, from Schultheiss et al., 1995.