English: The Early Cell Cycles of Histoblasts Are Fast and Synchronous and Lead to a Reduction in Cell Size (1–5 h APF) A single histoblast (arrow) in the anterior dorsal nest was labeled with GFP using the FLP-OUT/FRT system. The rest of the cells in the nest were marked using a nuclear His2-YFP (red). The GFP-positive cell divides with a cell doubling time of 2.5 h, generating a clone composed of four smaller cells.