cleavage stage [FBdv_00000054]

Stage during which the nucleus of the fertilized egg performs 13 rapid divisions, prior to cellularization (Hartenstein, 1993; Campos-Ortega and Hartenstein, 1997. The first seven divisions are synchronous (Campos-Ortega and Hartenstein, 1997. During the course of the subsequent three divisions, most of the nuclei approach the surface and then divide asynchronously a further three times, bringing the total number of cells to around 5000 (Campos-Ortega and Hartenstein, 1997. This corresponds to embryonic stages 1-4 (Hartenstein, 1993. (Hartenstein, 1993, Campos-Ortega and Hartenstein, 1997)