Bacterial Mutation Accumulation Experiments

Background

Generally, you will need a large number of individual lines. The power of this experiment to measure mutation rates is the number of lines analyzed times the number of generations.

Procedure

Setup

Revive a culture of your strain by streaking it out on an agar plate and growing. Resuspend a single well-isolated colony in saline, dilute and plate so that you will have a new agar plate (or plates) containing several hundred well-separated colonies after another growth cycle. Also grow a liquid stock of this original culture to freeze. This is your original clone.

Daily transfers

Transfer every day (or however many days every growth cycle takes). The timing should be as precisely the same as possible at eah transfer. Generally, stay within +/– 1 hr of the time of day from transfer to transfer. (Very occasionally you can leave the plates at 4°C for a day or two in case of emergency, but note than deviations from a well-controlled pattern, where the number of generations of growth, and their environmental conditions are kept constant at each transfer weakens the inferences that can be made from the data).

Archiving samples

References