Fig. 5.

Host shows broad spatial competence for the development of the secondary heart. (A) GATA4 injected reaggregates (CAG-GFP) were transplanted at stage 20 into host embryos (CAG-GFP) at the same stage in a number of different regions, as indicated by the number. (B, B′) 51% of transplants in the head showed GFP expression but did not beat (n = 20). (C–E′) Transplants in the lateral (position 5) and the caudal side (position 4) of host embryos developed beating SH as control ventral transplants. Transplant were all analysed at stage 39. (B, E′) lineage tracing (rhodamine dextran) of transplants whose cardiac GFP activity is shown in B′ and E, respectively. h, heart.