Confocal micrographs and 3D reconstructions of early cleavage stages of Loxosomella sp. Scale bars: 10 μm. left column: Nucleic acid staining (blue). A, C, F, I, L, O: lateral view; B, D, E, G, H, J, K, N: animal view; M: vegetal view. Polar bodies are indicated by arrowheads. Middle and right column: 3D reconstructions, middle column: animal view, right column: lateral view. grey: polar bodies, red: "macromere" quartet cells (nQ cells); purple, blue, light blue, green, yellow: "micromere" quartet cells (nqn cells). A-C: Fertilized oocyte prior to first cleavage. One polar body is present on the animal side of the embryo. D-F: Two-cell stage. A second polar body appears shifted by 90° relative to the first polar body. The macromeres are equal in size. Second polar body obscured by the red cells in E and F. G-I: Five-cell stage. Three polar bodies are present. Cleavage is asynchronous and the fifth cell (purple) lies between two Q cells (red) in a cleavage furrow. J-L: Eight-cell stage. Two polar bodies are present and located next to the vegetal, slightly unequal 1Q cells (red). Each cell of the first "micromere" quartet 1q (purple) is located in a cleavage furrow of two 1Q cells. M-O: 21-cell-stage. Cleavage is asynchronous, cells are different in size.
Merkel et al. BMC Developmental Biology 2012 12:11 doi:10.1186/1471-213X-12-11