2015/02/27 by Tiffany Taylor, Geraldine Mulley, Alexander Dills +7 · 2 citations
Biochemistry, Genetics and Molecular Biology · #Protist diversity and phylogeny #Photosynthetic Processes and Mechanisms #Bacterial Genetics and Biotechnology
paper · doi:10.1126/science.1259145
openalex publication_date 2015/02/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/04
A central process in evolution is the recruitment of genes to regulatory networks. We engineered immotile strains of the bacterium Pseudomonas fluorescens that lack flagella due to deletion of the regulatory gene fleQ. Under strong selection for motility, these bacteria consistently regained flagella within 96 hours via a two-step evolutionary pathway. Step 1 mutations increase intracellular levels of phosphorylated NtrC, a distant homolog of FleQ, which begins to commandeer control of the fleQ regulon at the cost of disrupting nitrogen uptake and assimilation. Step 2 is a switch-of-function mutation that redirects NtrC away from nitrogen uptake and toward its novel function as a flagellar regulator. Our results demonstrate that natural selection can rapidly rewire regulatory networks in very few, repeatable mutational steps.