Lecturer: Prof. Nathalie Q. Balaban
Affiliation: Racah Institute of Physics, Hebrew University of Jerusalem
Abstract:
The process of self-replication is at the core of
biological systems. Starting from a single
bacterium, self-replication can generate a
population of thousands of identical cells within a
few hours. Despite being genetically identical,
those cells may vary in many parameters including
levels of proteins, size, duration of self-replication,
etc. Often discarded as “noise”, this variability can
in fact unveil key processes in cells, with
important consequences for basic science, as well
as medicine. Typically, biological variability is
attributed to the stochastic processes inherent to
the physicochemical reactions that take place in
cells. However, a central question is whether the
observed variability can be attributed to
stochasticity only or whether it contains an
important deterministic component. We discuss a
mathematical framework that can distinguish
between stochasticity and determinism in the
inheritance of cellular properties during the self-
replication process. Using this framework, we
show that variability in the duration of self-
replication in mammalian cells follows a
deterministic process and present a deterministic
chaos model that reproduces the main
experimental features. Our approach constitutes a
general way to distinguish between stochastic and
deterministic processes in lineages of cells or
organisms, and may help predict and, eventually,
control cell-to-cell heterogeneity in various
systems, such as cancer cells under treatment.