What is the difference between CRISPR and ZFNs (zinc finger nucleases)?
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In contrast to CRISPR, the process of transfecting and selecting cells can be quite arduous and laborious. Also, the cost of multiple protein-DNA complex formation and recognition can be quite expensive when compared to merely injecting RNA targeted to the RISC.
Reference:
1. J. Doudna and E.J. Sontheimer. “The Use of CRISPR/Cas9, ZFNs, and TALENs in Generating Site-Specific Genome Alterations,” Methods in Enzymology 2014.