dre-mir-126a: Dre-mir-126a is a microRNA (miRNA) gene in zebrafish that has been studied for its potential role in gene regulation [PMC3737551]. Researchers have used TALENs (transcription activator-like effector nucleases) to target the upstream and downstream sequences of dre-mir-126a and miRNA Cluster Chr [PMC3737551]. PCR analysis showed that the deletion allele was dominant in the embryos injected with TALENs [PMC3737551]. The CRISPR/Cas gene-targeting system was also used to manipulate the dre-mir-126a locus, with gRNAs designed to target specific sequences [PMC3737551]. The efficiency of TALEN pairs correlated with the intensity of PCR products, indicating successful targeting [PMC3737551]. The CRISPR strategy has allowed for the deletion of genomic regions containing dre-mir-126a or miRNA cluster Chr.9 in zebrafish, with a success rate of 1% to 3% [PMC4613301]. Xiao et al. were the first to use CRISPR to eliminate large genomic regions in zebrafish, including dre-mir-126a or miRNA cluster Chr.9, which constitute a small percentage of the zebrafish genome [PMC5780079]. Overall, these studies demonstrate successful targeting and deletion of dre-mir-126a using TALENs and CRISPR/Cas systems in zebrafish embryos.