Figure 3. Helical motion of a single cell in transcriptome space.

Gene expression changes due to cell cycle can be simplified to a two‐dimensional circle by viewing the cylinder from the front or back. Additional cellular processes, suggested by GO terms to correspond to epigenetics and environmental changes, cause a helical motion around a hollow cylinder in transcriptome space. During one cell cycle period of time T, the cell moves parallel to the cylinder axis by $\mathrm{\Delta }{z}_T$.