Cellular development of a nematode: 3-D computer reconstruction of living embryos.

Embryos of the free-living soil nematodeCaenorhadditis elegans are capable of developing normally outside the mother; we have monitored this process in isolated embryos by light microscopy and recorded it on video tape. The size and position of each nucleus were entered into a computer at short time intervals from the 2- to 102-cell stages. Models were reconstructed in which nuclei are represented by spheres and assigned different colors and patterns according to lineage membership. Three-dimensional reconstructions aid visualization of the spatial arrangement of nuclei and demonstrate the small degree of positional variance among individuals. The dynamic processes of nuclear growth during the cell cycle, division, migration, and patern formation can be quantitatively analyzed. Our knowledge of the complete embryonic lineage allows the correlation of nuclear behavior with eventual cellular fate.