CRISPR/Cas technology allows rapid, site-specific genome modification in a wide variety of organisms. Proof-of-principle studies in Drosophila melanogaster have used various CRISPR/Cas tools and experimental designs, leading to significant uncertainty in the community about how to put this technology into practice. Moreover, it is unclear what proportion of genomic target sites can be modified with high efficiency. Here, we address these issues by systematically evaluating available CRISPR/Cas reagents and methods in Drosophila. Our findings allow evidence-based choices of Cas9 sources and strategies for generating knock-in alleles. We perform gene editing at a large number of target sites using a highly active Cas9 line and a collection of transgenic gRNA strains. The vast majority of target sites can be mutated with remarkable efficiency using these tools. We contrast our method to recently developed autonomous gene drive technology for somatic and germ line genome engineering and conclude that optimized CRISPR with independent transgenes is as efficient, more versatile and does not represent a biosafety risk.
- Received April 16, 2015.
- Accepted May 16, 2015.
- Copyright © 2015 Author et al.
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