Computational Model Reveals How DNA Replication Adapts to Cellular Stress
Researchers have developed a lattice-based stochastic Monte Carlo framework that models entire-genome DNA replication in yeast at single base-pair resolution under thermal, chemical, and genotoxic stress. The model incorporates probabilistic origin firing, fork-speed distributions, and a time-dependent limiting factor for cellular replication resources, benchmarked against experimental data. It offers a unified, two-parameter framework for understanding how replication dynamics break down or adapt under diverse stress conditions.
A new computational study posted to arXiv introduces a stochastic Monte Carlo model capable of simulating whole-genome DNA replication in Saccharomyces cerevisiae at single base-pair resolution. The framework accounts for probabilistic origin firing, heterogeneous replication fork speeds, and a time-varying limiting factor representing the availability of cellular replication machinery. After being validated against existing experimental replication profiles, the model was applied to stress scenarios including heat, hydroxyurea (a chemical replication inhibitor), and various genotoxic agents. A key finding is that fork-speed heterogeneity alone can explain the emergence of Erlang-distributed S-phase durations and rare, anomalously long replication events previously observed in E. coli and human cell lines, with the model predicting similar phenomena in yeast. The framework also forecasts non-monotonic responses to thermal stress and power-law scaling behavior under hydroxyurea, providing experimentally testable predictions across diverse stress conditions.
What's missing
As a preprint, this work has not yet undergone peer review, so its findings should be treated as preliminary. The model relies on only two effective parameters to reproduce diverse stress responses, which raises questions about whether this parsimony reflects genuine biological simplicity or an underfitting of more complex underlying mechanisms. The study does not address how well the yeast-derived model parameters would generalize to more complex eukaryotes, nor does it experimentally validate its novel predictions (e.g., non-monotonic thermal behavior in S. cerevisiae).
What different sources said
- arXiv q-bioCenter
DNA Replication under Thermal, Chemical, and Genotoxic Stress
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