Speaker
Description
Telomeres are repetitive sequences of DNA at the end of linear chromosomes. Their length decreases at each cell division, leading to replicative senescence in the absence of elongation mechanisms. In some unicellular organisms, as the yeast Saccharomyces Cerevisiae, telomere length homeostasis is maintained by the enzyme telomerase \cite{MF}. In liquid dilution experiments of yeasts with inactivated telomerase, emergence of cells presenting an alternative recombination-based mechanism (ALT) is observed after replicative senescence. The origin and dynamics of ALT cells are not yet well understood \cite{Kockler} and the goal of this talk is to present a stochastic modelling approach to characterize the time of emergence of ALT cells and the variability of their telomere distribution. An asymptotic analysis under a relevant parameter scaling, inspired by \cite{Champagnat}, allows us to account for experimental observations.
Bibliography
@article{Kockler,
title = {A unified alternative telomere-lengthening pathway in yeast survivor cells},
journal = {Molecular Cell},
volume = {81},
number = {8},
pages = {1816-1829.e5},
year = {2021},
issn = {1097-2765},
doi = {https://doi.org/10.1016/j.molcel.2021.02.004},
url = {https://www.sciencedirect.com/science/article/pii/S1097276521000903},
author = {Zachary W. Kockler and Josep M. Comeron and Anna Malkova}}
@article{MF,
title = {Life and {Death} without {Telomerase}: {The} \textit{{Saccharomyces} cerevisiae} {Model}},
volume = {17},
issn = {1943-0264},
shorttitle = {Life and {Death} without {Telomerase}},
url = {http://cshperspectives.cshlp.org/lookup/doi/10.1101/cshperspect.a041699},
doi = {10.1101/cshperspect.a041699},
language = {en},
number = {5},
urldate = {2026-07-01},
journal = {Cold Spring Harbor Perspectives in Biology},
author = {Martinez-Fernandez, Veronica and Barascu, Aurélia and Teixeira, Maria Teresa},
month = may,
year = {2025},
pages = {a041699},
}
@article{Champagnat,
author = {Nicolas Champagnat and Sylvie M{\'e}l{\'e}ard and Viet Chi Tran},
title = {{Stochastic analysis of emergence of evolutionary cyclic behavior in population dynamics with transfer}},
volume = {31},
journal = {The Annals of Applied Probability},
number = {4},
publisher = {Institute of Mathematical Statistics},
pages = {1820 -- 1867},
keywords = {bacterial conjugation, branching processes with immigration, coupling, Horizontal gene transfer, large population approximation, logistic competition, long time behavior, stochastic individual-based models},
year = {2021},
doi = {10.1214/20-AAP1635},
URL = {https://doi.org/10.1214/20-AAP1635}
}
