The emerging H3K9me3 chromatin landscape during zebrafish embryogenesis.

Eukaryotic genomes are organized into transcriptionally permissive euchromatin and repressive heterochromatin. However, we have a limited understanding of how these distinct states are first established during animal embryogenesis. Here, we define the emerging landscape of the heterochromatic histone tail modification H3K9me3 across zebrafish embryogenesis. Our results uncover distinct kinetics of H3K9me3 establishment and growth, define unique characteristics associated with initial sites of H3K9me3, and demonstrate additional maturation of the H3K9me3 landscape beyond the window of bulk H3K9me3 deposition.