Gene expression during the yeast cell cycle. In this figure, each gene corresponds to a row, and the time point for each column is denoted. The magnitude of mRNA expression ratio for each gene is represented by different colours. Red indicates mRNA abundance; green indicates a dearth; and gray indicates absence of the data. The colours at the top bar distinguish the cell cycle phases (M/G1, yellow; G1, green; S, purple; G2, red; M, orange).