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             Loss of gata4 and gata6 results in heart tube morphogenesis defects. ISH was performed using offspring from a gata4+/−, gata6+/− in-cross and probes targeting either myocardial marker myl7 or cardiac progenitor marker nkx2.5. (A) The gata4 and gata6 genes are partially redundant for heart tube elongation and looping. The gata4−/−, gata6−/− mutants display distinctly truncated and linear heart tubes. Representative scale bars in WT panels: 0.1 mm. (B) Loss of gata4 and/or gata6 does not affect cardiac specification. Error bars shown are s.e.m. (C) Schematic showing that combinatorial loss of gata4 and gata6 impairs the heart tube elongation stage of cardiogenesis. 
        
    
                        
                    
                
            
            
            
            
            
            
                
             
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