Biology subjects

Griffiths, A. D.

Publications and source records attributed to Griffiths, A. D..

2 recordsLinked to original sources

bioRxiv2019

Darwinian properties and their trade-offs in autocatalytic RNA networks

Discovering autocatalytic chemistries that can evolve is a major goal in systems chemistry and a critical step towards understanding the origin of life. Autocatalytic networks have been discovered in various chemistries, but we lack a general understanding of how network topology controls the Darwinian properties of variation, differential reproduction, and heredity, which are mediated by the chemical composition. Using barcoded sequencing and droplet microfluidics, we establish a landscape of thousands of networks of RNAs that catalyze their own formation from fragments, and derive relationships between network topology and chemical composition. We find that strong variations arise from catalytic innovations perturbing weakly connected networks, and that reproduction increases with global connectivity. These rules imply trade-offs between reproduction and variation, and between compositional persistence and variation along trajectories of network complexification. Overall, connectivity in reaction networks provides a lever to balance variation (to explore chemical states) with reproduction and heredity (persistence being necessary for selection to act), as required for chemical evolution.

evolutionary biology↗

bioRxiv2019

Metabolic Cost of Rapid Adaptation of Single Yeast Cells Under Unforeseen Challenge

Cells can rapidly adapt to changing environments through non-genetic processes; however, the metabolic cost of such adaptation has never been considered. Here we demonstrate metabolic coupling in a remarkable, rapid adaptation process (10-3cells/hour) by simultaneously measuring metabolism and division of thousands of individual Saccharomyces cerevisiae cells using a droplet microfluidic system. Following a severe challenge, most cells, while not dividing, continue to metabolize, displaying a remarkably wide diversity of metabolic trajectories from which adaptation events can be anticipated. Adaptation requires the consumption of a characteristic amount of energy, indicating that it is an active process. The demonstration that metabolic trajectories predict a priori adaptation events provides the first evidence of tight energetic coupling between metabolism and regulatory reorganization in adaptation.\n\nOne Sentence SummaryDemonstration of the tight coupling between metabolic activity and regulatory processes during rapid adaptation at the single-cell level.

systems biology↗