Search

Drought stress is a key limitation for plant growth and colonization of arid habitats. We study the evolution of gene expression response to drought stress in a wild tomato, Solanum chilense, naturally occurring in dry habitats in South America. We conduct a transcriptome analysis under standard and drought experimental conditions to identify drought-responsive gene networks and estimate the age of the involved genes. We identify two main regulatory networks corresponding to two typical drought-responsive strategies: cell cycle and fundamental metabolic processes. The metabolic network exhibits a more recent evolutionary origin and a more variable transcriptome response than the cell cycle network (with ancestral origin and higher conservation of the transcriptional response). We also integrate population genomics analyses to reveal positive selection signals acting at the genes of both networks, revealing that genes exhibiting selective sweeps of older age also exhibit greater connectivity in the networks. These findings suggest that adaptive changes first occur at core genes of drought response networks, driving significant network re-wiring, which likely underpins species divergence and further spread into drier habitats. Combining transcriptomics and population genomics approaches, we decipher the timing of gene network evolution for drought stress response in arid habitats., (© 2024 The Author(s). Molecular Ecology published by John Wiley & Sons Ltd.)

The escalating role played by managed care organizations in the health-care system is reflected in the increased demand for cost-effectiveness analyses (CEAs) to assess the balance between economic impact and clinical efficacy. For example, the high incidence and costs associated with colorectal cancer in Latin America calls for a comprehensive economic evaluation to ensure appropriate allocation of limited health-care funds. In addition, the current call for a "societal" perspective of such analyses indicates the need for increased consideration of the concerns of both patient and health-care provider. The introduction of oral tegafur and uracil (UFT) provided the opportunity to evaluate the pharmacoeconomic advantage of the new agent compared with the standard fluorouracil (5-FU). Results of this study indicated an economic advantage for oral UFT vs a 5-FU-based regimen in the treatment of colorectal cancer in Brazil and Argentina. It was further noted that the mild toxicity profile of UFT reduced both the number of clinic visits and the need for venipuncture procedures. Noting that oral UFT may have a positive impact on quality of life in addition to its estimated economic benefit, it was concluded that prospective economic research and quality-of-life evaluations are needed to fully assess the pharmacoeconomic impact of oral UFT.