(a) qPCR quantitation of mutational efficiency in injected embryos for each of the failed target sgRNAs from the screen and a newly synthesized version. Each was individually injected at 100/1,200 pg sgRNA/Cas9-encoding mRNA. Mutation efficiency was assessed by qPCR and was done in triplicate; error bars denote s.e.m. (b) nrxn1b_S contained two polymorphisms in the designed sgRNA as compared to the genomic sequence of the fish into which it was injected. These differences likely reflect its failure to induce indels. In a, each bar represents five embryos pooled in three replicates; error bars denote s.e.m.