Investigating temporal stereotypy in ascidian embryos development

Developmental biology explores the mechanisms of embryo formation and development. Here, we focus on ascidian embryo development, which is highly stereotyped, allowing the identification of homologous cells across embryos and thereby enabling the analysis of embryogenesis at the cellular level. In a population of ascidian embryos, cells may divide in different orders across individuals, yet division rates remain similar overtime, resulting in a conserved total cell count at any given timepoint between different embryos. This raises the question of what conditions are necessary to maintain this conservation. To address this, we simulated the evolution of cell counts in a population of ascidian embryos imaged under the microscope. Our results suggest that the conservation of cell count emerges from a tissue-dependent cell lifetime stereotypy. These results provide new insights into the mechanisms underlying the conservation in cell count during ascidian embryogenesis.