Morino Yoshiaki
Assistant Professor, Faculty of Life and Environmental Sciences, University of Tsukuba
Mechanism and evolution of blastomere fate allocation in spiral cleavage-type development

Reasons for the Award: In contrast to the "radial cleavage" seen in the early development of sea urchins and frogs, flatworms, ribbon worms, mollusks, and annelids undergo a characteristic cleavage known as "spiral cleavage." Cleavage is important for the determination of developmental fate along the animal-vegetal axis of the egg, and the elucidation of the mechanisms controlling this at the molecular level has been eagerly awaited. Member Komei Morino tackled this problem using the mollusk *Nipponacmea fuscoviridis* and the annelid *Hydroides elegans* as experimental materials. Through database searches, gene expression analysis, and functional analysis using the microinjection method, he revealed that a group of homeobox transcription factors specific to spiral-cleavage animals (named SPILE genes) are involved in cell fate determination. This achievement, which elucidates the molecular entities involved in the cell fate determination mechanism of spiral-cleavage-type development, is groundbreaking and has a major impact on a wide field of invertebrate embryology. This research is also extremely unique in that it enabled comprehensive gene functional analysis by utilizing bioinformatics in non-model marine invertebrates, leading to the decision to award the Narishige Zoological Science Promotion Award to Member Morino.