Interaction between GATA4 and GATA6 in heart and liver development. Suboptimal doses of G4 (A, 25 ng) or G6 (B, 5 ng) MOs have only minor effects on heart and liver development at st. 37. 50 ng of G4 MO (C, D) or 10 ng of G6 MO cause heart and liver defects. Similar defects are seen in embryos coinjected with 25 ng of G4 MO and 5 ng of G6 MOs (F). G, H: 50 ng/embryo of C1 MO has no effect on heart and liver. I-frequencies of the phenotypes observed. Heart and liver precursor have been analysed as in Fig. 1 with MLC2 and Hex markers.