Fast Growth Increases the Selective Advantage of a Mutation Arising Recurrently during Evolution under Metal Limitation

The goal was to use microarray to compare changes in the global transcription profiles between an engineered bacterial strain and one of its descendants subject to 600 generations of experimental evolution in batch culture. This comparison allowed us to identify a beneficial mutation that substantially increased expression of a novel cobalt transporter cassette in this descendant. The total RNA of the an engineered strain of Methylobacterium extorquens AM1 and an descendant derived from this engineered strain was extracted. RNA extractions were performed 3 times using 3 independent growth cultures of a given strain. The final RNA samples for the following microarray experiments consisted of an equal proportion of 3 independent extractions for each strain. The cDNA of the descendant was labeled with Alexa_555 while the engineered strain was labeled with Alexa_647 in the array dataset GSM371896.