Fig. 4. Timing of animal restriction. (A) Animal and vegetal reporter expression at the 16-cell stage as visualized by lacZ mRNA detection. Lateral views, anterior to the left, numbers indicate the proportion of positive embryos with restricted expression. (B) At the 8-cell stage, the mRNA expression of animal and vegetal markers is partially restricted. Representative embryos are shown across the top; diagram of experimental results at the bottom. Red indicates the percentage of embryos with stronger animal expression; white indicates equal animal and vegetal expression; yellow indicates stronger vegetal expression. Numbers of embryos counted are indicated on the colored bars.