Active regulation of growth and division controls the spatio-temporal organization of living organisms

Biological systems such as developing organisms, growing tissues, or expanding bacterial biofilms depend on two key processes—cell division and growth. While division increases cell numbers, growth enlarges individual cells. These active processes shape large-scale properties such as division waves, mechanical state transitions, ordered spatial arrangements, and cell size regulation. Though division and growth are often coupled, they can also operate independently, complicating their influence on tissue mechanics and organization. For example, spatially coordinated division and its role in pattern formation have been underexplored, especially in particle-based models that account for individual cell dynamics. This project, GrowDiv, focuses on understanding how biological systems with uncoupled division and growth achieve robust spatial and temporal organization.Working closely with experimentalists studying the self-organization of Xenopus laevis embryo cytoplasm, I will use a numerical particle-based model to investigate the impact of growth and division timescales on three major transitions: (i) from steady division waves to chaotic dynamics, (ii) from fluid to solid-like states, and (iii) from ordered spatial arrangements to disordered configurations. In particular, I will simulate how independent growth and division lead to stable organization, comparing theoretical predictions to experimental results on cytoplasmic dynamics and microtubule asters. The project will reveal how large-scale biological self-organization emerges from the intricate interplay between division and growth, providing deeper insights into early embryogenesis and the mechanical properties of living systems.