Targeting of the f5 locus using genome editing produces a null allele. (A) Structure of human F5; residue numbering is from the human protein. The CRISPR/Cas9-induced mutation deletes what would be human residues 143 through 160 in the A1 domain and induces a frameshift. Numbered positions indicate location of human mutations evaluated in Figure 5. (B) Sequence of 49-bp f5 exon 4 deletion. (C-D) Amplification of genomic and cDNA from f5^+/+, f5^+/−, and f5^−/− fish demonstrates the 49-bp deletion with no evidence for any other products.