Geometry-driven asymmetric cell divisions pattern cell cycles and zygotic genome activation in the zebrafish embryo

Abstract Early embryo geometry is one of the most invariant species-specific traits, yet its role in ensuring developmental reproducibility and robustness remains underexplored. Here we show that in zebrafish, the geometry of the fertilized egg—specifically its curvature and volume—serves as a critical initial condition triggering a cascade of events that influence development. The embryo geometry guides patterned asymmetric cell divisions in the blastoderm, generating radial gradients of cell volume and nucleocytoplasmic ratio. These gradients generate mitotic phase waves, with the nucleocytoplasmic ratio determining individual cell cycle periods independently of other cells. We demonstrate that reducing cell…

• IO
  Institute of Science and Technology Austria

  Award: 754411
• EC
  European Commission

  Awards: 754411, 101034413
• NS
  NOMIS Stiftung