EXTERNAL SEMINAR - Nicoletta Petridou (EMBL Heidelberg)

Nicoletta Petridou (EMBL Heidelberg) will give a short external seminar, hosted by Thomas Lecuit (IBDM).

Location: Hexagone Auditorium
Date: 11.05.2026
Time: 1:30 PM

CENTURI is also providing for off-campus participants only a zoom link to attend the seminar: https://us02web.zoom.us/j/85941690095?pwd=Nm5NVGhESGlUbG1FMnZ2dU5vSlkxUT09

Meeting ID: 859 4169 0095
Secret Code: 002024

Timing, Noise and Collectives: How cell cycles shape the early embryo

Across several metazoans, early embryos exhibit a strikingly conserved slowing down of their cell duplication speed together with an increasing variability, despite widely varying developmental paces and underlying molecular mechanisms. Here we show that this universal behaviour arises because early development unfolds along a biochemical, not chronological, timescale, driven by the consumption of finite maternal resources coupled to Michaelis–Menten kinetics of the enzymatic reactions involved in cell division. This leads to a hyperbolic growth of the Cell Cycle Length (CCL), approaching a mathematical singularity. Data from diverse animals —cnidarians, nematodes, arthropods, molluscs, echinoderms, tunicates, amphibians and fish— collapse on a single curve, quantitatively predicting, not only CCL dynamics, but also related hallmarks of early metazoan embryogenesis, including cell number evolution, CCL dependency on cell size, and gastrulation timing at the predicted singularity. Alongside these deterministic dynamics, cell-to-cell heterogeneity in CCL arises from stochastic differences in resource allocation during cell divisions. Due to the underlying hyperbolic growth, the cell-to-cell differences in resource availability are inherited and deterministically amplified across generations, causing explosive but structured dynamics in cell cycle disorder. Experiments in zebrafish early embryos together with large-scale 3D simulations identify an optimum level of variability at which long-range cell-cell contact remodelling occurs timely and robustly, initiating collective tissue morphogenesis. Our findings uncover how the interplay between deterministic resource constraints and optimal CCL variability drives the timing and collective mechanics of early vertebrate morphogenesis.