Figure 1

Vector sum based on oscillation and phase. For a gene, each time course is represented by a vector such that the Periodicity and Expression scores determine the magnitude of the vector, and the cell cycle phase of peak expression gives the direction of the vector. Plot (a) shows two hypothetical time courses with similar phases of peak expression (both peaking in G2 phase). In (a), the sum of the two vectors u+v yields a vector (plotted in grey) with a greater magnitude than either of the component vectors. Plot (b) shows two time courses with dissimilar phases of peak expression, one peaking at the beginning of M phase, and the other peaking just after S-phase. The sum of these two vectors u+v yields a vector (in grey) with a lower magnitude than either of the component vectors. The colored circumference refers to the circular distribution of cell cycle phases in S. pombe (red-G2, green-M, purple-G1, blue-S) in both plots.