Generation of MZdnmt3aa^-/- zebrafish mutant (A) The dnmt3aa genomic DNA sequence and CRISPR/Cas9-mediated indel mutation, with predicted amino acid sequences, in WT and MZdnmt3aa^-/- mutants are shown. The MZdnmt3aa^-/- mutants have a 5-bp deletion which leads to a frame-shift at amino acid 13^th position. The schematic diagram shows predicted protein products from the WT and the mutant alleles. It is speculated that the deletion mutation results in the production of a truncated protein with additional sequences (red box) at the C-termini. Putative functional domains (PWWP, cysteine-rich ATRX-Dnmt3-Dnmt3L (ADD), and methyltransferase domains) in the WT protein are represented as grey colored boxes. (B) Gross morphology of the MZdnmt3aa^-/- mutant is identical to WT at 2 dpf. Scale bar: 1 mm.