A frameshift mutation did not phenocopy the corresponding Morpholino. To avoid transcriptional adaptation (genetic compensation), the authors made mutants with deleted promoters, eliminating the NMD transcript that would trigger transcriptional adaptation.
Generating Zebrafish RNA-Less Mutant Alleles by Deleting Gene Promoters with CRISPR/Cas9.
Kumari P, Sturgeon M, Bonde G, Cornell RA. Methods Mol Biol. 2022;2403:91-106. doi: 10.1007/978-1-0716-1847-9_8.