Accurate characterization of CRISPR-Cas9 genome editing outcomes and mosaicism with near-perfect long reads.

PureTarget PacBio sequencing reveals widespread genetic mosaicism with up to 18 on-target and 11 off-target variants in individual zebrafish founders.

• Why it matters: Understanding mosaicism is crucial for accurate interpretation of CRISPR-Cas9 editing outcomes, especially since low-frequency structural variants are difficult to detect with traditional methods.
• What they did: Researchers performed amplification-free, high-accuracy PacBio sequencing on 30 samples from genome-edited zebrafish, achieving over 1100x coverage and QV39 read accuracy to analyze editing outcomes and inheritance.
• The result: Findings demonstrate extensive mosaicism, with multiple unique editing events inherited by offspring, highlighting the importance of precise profiling for assessing genome editing safety and efficacy.