@article {166225, title = {Adaptation to extreme stress under the growth-survival fitness trade-off}, journal = {Phys. Rev. E}, volume = {113}, year = {2026}, month = {May}, pages = {054403}, abstract = {

Microbial adaptation to extreme stress, such as starvation, antimicrobial exposure, or freezing, often reveals fundamental trade-offs between survival and proliferation. Understanding how populations navigate these trade-offs in fluctuating environments remains a central challenge. We develop a quantitative model to investigate the adaptation of populations of yeast (Saccharomyces cerevisiae) subjected to cycles of growth and extreme freeze-thaw stress, focusing on the role of quiescence as a mediator of survival. Our model links key life-history traits{\textemdash}growth rate, lag time, quiescence probability, and stress survival{\textemdash}to a single underlying phenotype, motivated by the role of intracellular trehalose in the adaptation of yeast to freeze-thaw stress. Through stochastic population simulations and analytical calculation of the long-term growth rate, we identify the evolutionary attractors of the system. We find that the strength of the growth-survival trade-off depends critically on environmental parameters, such as the duration of the growth phase. Crucially, our analysis reveals that populations optimized for growth-stress cycles can maintain viability alongside growth-optimized populations even in the absence of stress. This demonstrates that underlying physiological trade-offs do not necessarily translate into fitness trade-offs at the population level, providing general insights into the complex interplay between environmental fluctuations, physiological constraints, and evolutionary dynamics.

}, doi = {10.1103/nppw-z5lv}, url = {https://link.aps.org/doi/10.1103/nppw-z5lv}, author = {Chaturvedi, Nandita and Tvishamayi, Charuhansini and Thutupalli, Shashi} } @article {149409, title = {Evolutionary Adaptation in Heterogeneous and Changing Environments.}, journal = {Evolution}, year = {2024}, month = {2024 Oct 09}, abstract = {

Organisms that are adapting to long term environmental change almost always deal with mul- tiple environments and trade-offs that affect their optimal phenotypic strategy. Here we combine the idea of repeated variation or heterogeneity, like seasonal shifts, with long-term directional dy- namics. Using the framework of fitness sets, we determine the dynamics of the optimal phenotype in two competing environments encountered with different frequencies, one of which changes with time. When such an optimal strategy is selected for in simulations of evolving populations, we observe rich behavior that is qualitatively different from and more complex than adaptation to long-term change in a single environment. The probability of survival and the critical rate of environmental change above which populations go extinct depend crucially on the relative fre- quency of the two environments and the strength and asymmetry of their selection pressures. We identify a critical frequency for the stationary environment, above which populations can escape the pressure to constantly evolve by adapting to the stationary optimum. In the neighborhood of this critical frequency, we also find the counter-intuitive possibility of a lower bound on the rate of environmental change, below which populations go extinct, and above which a process of evolutionary rescue is possible.

}, issn = {1558-5646}, doi = {10.1093/evolut/qpae144}, author = {Chaturvedi, Nandita and Chatterjee, Purba} }