A blastoporal organizer in a ctenophore

Researchers identified a blastoporal organizer in the ctenophore Mnemiopsis leidyi on June 17, 2026, suggesting a key innovation for animal multicellularity. This discovery, detailed in Nature, utilized experiments with the comb jelly Mnemiopsis leidyi and the sea anemone Nematostella vectensis. The study indicates that the emergence of a core signaling pathway associated with the blastopore, the first opening formed during embryonic development, played a crucial role in the evolutionary transition from single-celled to multicellular organisms. This finding challenges previous assumptions about the independent evolution of developmental processes in different animal lineages. The presence of this organizer in ctenophores, which diverged early in animal evolution, provides significant insights into the ancestral mechanisms of animal development. The research team's comparative analysis between Mnemiopsis leidyi and Nematostella vectensis highlights conserved and divergent developmental strategies across early-branching metazoans. Understanding these ancient developmental pathways is fundamental to reconstructing the evolutionary history of animals and the genetic toolkit that enabled their diversification.