Researchers published a Nature study describing prime assembly, a genome-engineering method that supports targeted integration of long DNA fragments into programmable positions in living cells. The approach uses CRISPR-targeted dual flap synthesis, extending prime editing beyond small base changes by enabling larger, permanent insertions and rearrangements. The authors reported activity in both dividing and non-dividing cells and demonstrated targeted exon recoding, transgene integration, and megabase-scale rearrangements at therapeutically relevant loci in primary human cells. Compared with homology-directed repair, prime assembly is positioned as more targeted and to avoid double-strand breaks and donor requirements that can introduce toxicity and cell stress. If the efficiency and safety profile translate to broader systems, prime assembly could expand the feasibility of universal gene therapy concepts by reducing the need for patient-specific edits.