Researchers reported engineering CRISPR‑associated transposons (CASTs) with mutations that boost on‑site gene insertion activity up to fourfold while preserving high targeting specificity, advancing RNA‑guided DNA integration as a potential therapeutic platform. The team deployed a high‑throughput dual genetic screen to quantify activity and specificity across large CAST variant libraries and identified mechanistic mutations in core transposition components. Separately, broader improvements to gene‑editing toolkits—described as 'sharper gene scissors'—were reported across the field, expanding precise editing options beyond classical nucleases. Scientists emphasized the translational challenge of moving these engineered systems into human cells but framed the work as a significant step toward precision gene replacement therapies.