A cellular basis for the hourglass pattern in vertebrate embryogenesis (opens in new tab)

Vertebrate embryogenesis follows a conserved trajectory, exhibiting divergence in early and late stages and conservation during mid-embryogenesis across species. This pattern, known as the developmental hourglass, was first described at the morphological level and later supported by molecular studies, establishing it as a hallmark of vertebrate development. The “waist” of the hourglass, representing the period most resilient to evolutionary change, coincides with the emergence of the body pla...