Comparing and Contrasting the Role of the Segmentation Clock in Early Development Across Mammalian Species

Abstract: Understanding the segmentation clock across species provides insight into the evolution of complex life. However, despite decades of research, a comprehensive and unified understanding of its regulatory mechanism remains incomplete. This study provides a comprehensive overview of current knowledge on the segmentation clock and identifies key gaps requiring further investigation. Collectively, previous research has shown that the segmentation clock is a molecular oscillator that controls the periodic formation of somites. It relies on transcriptional receptors, such as the Hairy/Hes family of genes, and is a conserved developmental feature among vertebrate species. Recent advances in technology, specifically the development of in vitro stem cell models and improvements in live imaging techniques, have created more feasible and ethical means of examining segmentation behavior, especially in human cells. This paper critically analyzed and synthesized existing knowledge through a narrative review of the segmentation clock, including its historical background, recent developments, and future directions for the field.