Researchers reported a new prime assembly approach in Nature that enables targeted genomic integration of long DNA fragments into programmable locations in living cells. The method uses CRISPR-targeted dual flap synthesis, building on prime editing to assemble larger, permanent DNA edits without relying on homology-directed repair donors. The work demonstrated targeted exon recoding, transgene integration, and megabase-scale rearrangements in primary human cells, with the authors highlighting potential reductions in off-target toxicity compared with more insertion-prone, break-dependent strategies. A key technical distinction is that prime assembly is active in both dividing and non-dividing cells. For gene therapy developers, the update strengthens the toolkit for “universal” or broadly applicable gene therapies by expanding beyond short edits—though clinical translation will depend on delivery, efficiency, and safety profiling at scale.