Speaker: Todd Young (Ohio University)

Title: Models of Cell Cycle Dynamics and Clustering

Abstract: We study phenomenological ODE models of the cell cycles of large numbers of cells, with cell-cycle dependent feedback. We assume very general forms of the feedback and study the dynamics, particularly the temporal clustering behavior of such systems.

Biologists have long observed periodic oxygen consumption oscillations in yeast populations under certain conditions. Motivated by experiments, we hypothesized that some of these oscillations could be accompanied and/or caused by cell cycle clustering. We study models of the cell cycle in which cells in one phase of the cycle may influence the progress of cells in another phase (presumably by production or depletion of diffusible chemical products.) We give proofs of the existence and stability of certain periodic solutions in which cells are clustered. Furthermore, this clustering phenomenon is robust; it occurs for a variety of models and a broad selection of parameter values in those models. Related experiments show that cell cycle clustering occurs in the oscillating cultures.