Fig. 6.

Early bias of mouse blastomeres towards lineage fate but not axial polarity. Two-cell blastomeres undergo rotational cleavage (dotted white lines indicate cleavage planes), generating a fraction of embryos with a tetrahedral cell arrangement. In this formation, vegetal blastomeres are biased towards contributing to the trophectoderm (dark gray) in the blastocyst. The corresponding animal blastomeres are biased towards contributing to the inner cell mass (blue). After Zernicka-Goetz et al. (2009)