eLife Assessment
This study provides a useful analysis of the changes in chromatin organization and gene expression that occur during the differentiation of two cell types (anterior endoderm and prechordal plate) from a common progenitor in zebrafish, together with investigations into the molecular factors involved. Although the findings are consistent with previous work, the evidence presented appears to be incomplete and would benefit from more rigorous quantification of live imaging and Cre-Lox experiments, a stronger rationale and controls for experiments manipulating chromatin remodeling factors, and a strong justification for the explant model especially given differences between explant and whole embryo data. This work may be of interest to zebrafish developmental biologists investigating the mechanisms underlying specification.