Evolutionary gear shifting in a bacterial nano motor

Evolutionary adaptation and innovation are believed to be facilitated by the hierarchical modular architecture of organisms. Although this notion is very well supported by comparative evidence, real-time experimental insight into the evolutionary dynamics of complex phenotypes is limited. This project uses the bacterial flagellum—a helical propeller connected to a biological nano motor that bacteria use to swim—as a model to quantify the evolutionary modularity of a complex phenotype and examine the evolvability it affords. Our approach combines experimental bacterial evolution, directed protein evolution, microbial physiology and single molecule biophysics to (i) explore the extent to which mutation recombination affect modular phenotypic change, determine the patterns of adaptive trajectories under different regimes of genetic variation, and (iii) examine the evolutionary origin and maintenance of specialized modules via gene duplication & divergence.

Evolution and co-existence of bacterial survival strategies

Much of life's diversity has evolved during adaptive radiations: the rapid evolution of niche specialist from a single ancestor in heterogeneous environments. Using an experimental model system in which bacteria undergo adaptive radiation in real-time (Pseudomonas fluorescens), this project examines how selection imposed by the environment interacts with the evolutionary potential-that is, evolvability-of the bacteria to shape the evolution of niche specialists with different levels of specialisation.

Probing the creative potential of random mutations.

Random mutation is the ultimate source of novelty in evolution. are using a bacterial transcription factor to probe how mutations can tune its functional properties. Using directed mutagenesis and high-throughput characterisation of the mutated transcription factors in vivo and in vitro, we are exploring its local genotype- phenotype map. The work focuses on (i) the distribution of mutational effects on phenotype and evolvability, (ii) the relationship between phenotypic robustness and evolvability and (iii) the potential of neutral networks to facilitating evolvability.

Evolutionary dynamics of synthetic genetic circuits

Biological gene regulation networks cover a broad range of dynamics. We are using synthetic genetic circuits to examine how evolution tunes the behaviour of clearly defined circuits. On the basis of high throughput selection at the single-cell level, we create artificial environments to impose a range of selective pressures to probe evolutionary response. The work seeks insight into mechanisms by which evolution can modify the interactions between the circuit components to optimise gene regulation in different environments.