 0\) If Nodal signaling is mediated by heterodimers of Nodal and Vg0, the extent of Nodal signaling should depend on their stoichiometry. It would be interesting to overexpress different relative amounts of Vg0 and Nodal ligand in Vg0 mutant and analyse Nodal signaling activation (via Smad0 nuclear localization for instance).  We thank the reviewer for this suggestion. Please see our last response to point 0 above.  > 0\) The authors provide a simple theoretical model to show how the presence of maternally contributed Vg0 speeds up Nodal signaling upon production of Nodal ligands. I feel this is not particularly revealing: the idea that one component of a pathway being readily available speeds up signaling does not require modeling to be put forward. Moreover, the model is based on parameters measured or inferred for the Nodal ligands, which do not necessarily hold true for Vg0.  