Superfast evolution observed in soil bacteria

Pseudomonas fluorescens

Two mutations allowed soil bacteria (Pseudomonas fluorescens) to re-evolve flagella: One pumped up levels of a protein than controls nitrogen uptake, and one that switched that protein’s job to flagella production control.

Ninjatacoshell/Wikimedia Commons (CC BY-SA 3.0)

You can take the flagella out of the bacteria, but you can’t take the flagella out of the bacteria’s genetic arsenal.

By deleting a gene that controls flagella growth, Tiffany Taylor of the University of Reading in England and colleagues engineered the soil bacteria Pseudomonas fluorescens so they lacked their tiny tails. Bacteria that can move around and find food are more likely to survive, and after a mere 96 hours in a low-food environment, the bacteria were once again growing flagella.

How did the bacteria manage such a swift feat? Two mutations in regulatory genes jump-started flagella production, suggesting that natural selection can rewire genetic networks with a few key mutations, the researchers report February 26 in Science.

Helen Thompson

Helen Thompson is the multimedia editor. She has undergraduate degrees in biology and English from Trinity University and a master’s degree in science writing from Johns Hopkins University.

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