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Fig. 2 FGF signaling is necessary for proper CPC migration but not cardiac laterality during jogging. (A) Schematic depicting the 19-24 hpf SU5402 treatment window during the ‘jogging phase’. (B) RNA ISH for myl7 at 26.5 hpf visualizing correct left-sided positioning and incorrect midline and right-sided positioning of the heart tube. (C) Quantification of cardiac laterality phenotypes. WT, n=534; ntl−/−, n=113; spaw−/−, n=138; SU5402, n=112; dn-fgfr1, n=75; ntl−/−+SU5402, n=12; spaw−/−+SU5402, n=30; spaw−/−+MEK, n=14. Chi-square analysis. (D) RNA ISH for myl7 at 24 hpf displaying the stages from cone through extending to correctly jogged heart tubes observed in treated embryos. (E) Quantification of cardiac migration phenotypes. WT, n=686; ntl+/− sibling, n=213; ntl−/−, n=152; spaw+/− sibling, n=87; spaw−/−, n=171; SU5402, n=531; dn-fgfr1 WT sibling, n=66; dn-fgfr1, n=225; ntl−/−+SU5402, n=117; spaw−/−+SU5402, n=146; spaw−/− control injection, n=105; spaw−/−+MEK, n=35. Chi-square analysis. (F) Quantification of heart tube length at 26.5 hpf. WT, n=84; spaw−/−, n=62; SU5402, n=80; spaw−/−+SU5402, n=9. Statistical significance determined by an unpaired two-tailed Student's t-test. (B,D) Images are dorsal views, with anterior to the top and left to the reader's left. *P<0.05, **P<0.001, ***P<0.0001. ns, not significant. Error bars represent s.d.