Spatially Constrained Growth Enhances Conversional Meltdown

Area of Science:

• Cell biology
• Evolutionary dynamics
• Statistical physics

Background:

• Cellular differentiation and mutation can be irreversible processes.
• Maintaining a balance between cell conversion and selection is crucial for population stability.
• Spatial factors can influence the dynamics of cell populations and their fitness.

Purpose of the Study:

• To investigate the impact of spatial confinement on cell type stability.
• To explore the balance between cell conversion and selection in different growth geometries.
• To model cell population dynamics using principles from nonequilibrium statistical physics.

Main Methods:

• Utilized a genetically engineered yeast strain with fluorescent markers for cell tracking.
• Experimentally varied growth rates and conversion rates in different spatial conditions.
• Developed analytical models based on directed-percolation theory for various geometries.

Main Results:

• Populations on flat agar surfaces showed increased susceptibility to fitness loss compared to well-mixed populations.
• Analytical predictions for different geometries (liquid media, 2D colonies, linear fronts) were developed.
• The models showed consistency with experimental observations.

Conclusions:

• Spatial geometry critically affects the balance between cell conversion and selection.
• Flat surfaces pose a higher risk of population decline due to cell differentiation.
• Nonequilibrium statistical physics provides a useful framework for understanding these cellular dynamics.