Speaker
Description
In a study involving members of Marie Doumic's group at Ecole Polytechnique (Palaiseau, France) and Maria Teresa Teixeira's group at the Institut de Biologie Physico-Chimique (Paris, France), we present a stochastic model of growth of a cell population of cultured yeast cells with gradually decaying chromosome endings, called the telomeres. Telomeres play a major role in aging and carcinogenesis in humans. The model has the form of the age-dependent Markov branching process with doubly-denumerable type space, where the type of a cell is defined as the pair of integers representing the length of telomeres at both ends of a chromosome. We derive the forward and backward Kolmogorov equations for the generating functions characterizing the process, and find that the general solutions have the form of exponential polynomials. We further derive a recursion for the coefficients of the polynomials that leads to symbolic computations. A symbolic computation computer code is used in conjunction with Monte Carlo simulations to understand the dynamics of the process, also based on previous works of Olofsson and Kimmel and members of Doumic's group. We further consider models of reconstruction of telomeres, involving cell death and the ALT mechanism, using properties of slightly supercritical branching processes, conditional on non-extinction.
