Figure 1.

Natural variability in genome-wide gene expression. (a) Distributions of genome-wide gene expression variability F (t) among natural S. cerevisiae strains across the cell-division cycle (CDC), and the number of genes exhibiting positive (+), stabilizing (-), or no selection (0) at each timepoint (FWER < 0.05). Average variability profile (red line) exhibits a maximum fold change of 1.95. (b) Proportion of genes under stabilizing selection over time for eight life-cycle terms, ranked by average proportion. Numbers of associated genes are shown in parentheses. See Figure S4 in Additional file 1 for profiles of GO Slim terms. (c) Average budding index for natural S. cerevisiae strains. (d) Histogram of the number of timepoints for which a gene's CDC-expression trajectory undergoes stabilizing selection, partitioned into stabilized, partly neutral, and neutral categories. (e) Enrichment of life-cycle terms among neutral genes. * indicates significant enrichment (FDR < 0.05).