Mutations in global carbon catabolite repression genes give rise to diversified growth behaviors.

<p>Sequencing of the genomes of isolates with shorter lag phases isolated after repeated cycling between glucose and maltose medium revealed mutations in two genes, <i>STD1</i> and <i>HXK2</i> (see text for details). (A) Sanger sequencing confirmed the presence of multiple <i>HXK2</i> mutations and one <i>STD1</i> mutation in the evolved short-lagged strains. (B) Single-cell lag profiles of independent transformants of the ancestral strain bearing either WT (red and purple traces) or evolved (blue traces) <i>HXK2</i> alleles. Black traces correspond to the original evolved strains; the finely dotted line is Isolate 1 and the coarsely dotted line is Isolate 2. (C) Same as (B) but for the <i>STD1</i> allele identified in Isolate 3. Shown in blue are two independent transformants bearing Isolate 3's <i>STD1</i> allele.