Extended Data Fig. 10: Anterior cartilage development and roles for foxa2 and foxa3 during notochord development.

a, Anterior dorsal views of alcian blue-stained zebrafish embryos from 36 hpf to 72 hpf. b, Dorsal images of alcian blue-stained notochords at 36 and 48 hpf. c, Representative images of foxa2, foxa3, or foxa2;foxa3 crispants at ~48 hpf. d, Trunk sections for col2a1a in situ hybridizations. No notochord cells are present in double foxa2;foxa3 crispants. Scale bars, 100 µm. e, An updated model of the independent genetic requirements for PC and notochord development. Both structures derive from an early population of axial mesodermal progenitor cells. Cells that eventually become the notochord require foxa2, foxa3, noto, and tbxta, whereas tbxta is not required for the specification differentiation of axial mesodermal cells into the PC. (notochord is depicted in green and PC is depicted in purple at 3 dpf when PC is maturing).