Before revision:  The stereotypic pattern in early C. elegans embryo is  one of the most optimal solutions taking minimum time to achieve the cell number before gastrulation . Our methods lay a foundation for deciphering principles of development and guiding designs of bio-system .
After revision:  The stereotypic pattern in early C. elegans embryo is one of the most optimal solutions taking minimum time to achieve the cell number before gastrulation , by programming asymmetric division as a strategy .