Fig. 1. Nomarski photomicrographs of wild type (A-F) and spn-4(or80) (G-L) embryos. Photographs of wild-type and spn-4 embryos were taken at equivalent time points. Arrows point at centrosomes, and cell names are indicated. (M) Schematic drawings illustrate spindle angles observed at the one-cell and two-cell stages in wild-type and spn-4 embryos (see Materials and Methods). Each dash at the periphery of a quadrant represents a single scored embryo. In wild type, P₀ spindle angles range from 4° to 14° (n=6), the AB spindle angles range from 74° and 89°, and the P₁ spindle angles from 0° to 12° (n=11). In spn-4 mutant embryos, the following ranges were observed: or25 ‘P₀’ varied from 3°-12° (n=5), or25 ‘AB’ and or25 ‘P₁’ varied from 58°-89° and 32°-89° (n=11); or80 ‘AB’ and or80 ‘P₁’ varied from 61°-89° and 7°-89° (n=8); or191ts ‘AB’ and or191ts ‘P₁’ varied from 26°-90° and 7°-72° (n=8).