 The study identifies three conserved notochord-specific enhancers in the mammalian brashiri-T-TB-XT gene, which are responsible for controlling its expression in the notochord and causing specific trunk and neural tube defects when deleted. These enhancers are conserved beyond mammals in the brashiri-TB-XTB lochia fishes and convey robustness and adaptability as an ancient basis for axis development. This article was offered by Cassie L. Kemler, Jana Smolakova, Hannah Amaran, and others.