Fig. 3.

LCB2 and LCB1 gene expression levels covary among wild strains of Saccharomyces cerevisiae and between growth environments. LCB2 gene expression is upregulated in osmotic stress media (blue points) in comparison with levels of expression in standard media (orange points). LCB2 levels are significantly lower in wild strains YJM145 and RM11-1a than in the auxotrophic lab strain R1158, suggesting that the expression–fitness function has evolved in the lab strain (asterisk; two-tailed t test, P = 0.028 and P = 0.047, respectively). Fold change was ascertained by qPCR and is relative to the expression level of the same gene in the lab strain (R1158) when grown in standard media. Standard errors of three or more biological replicates are shown.