Researchers reported a new donor design that allows safe insertion of kilobase‑scale DNA into mammalian genomes without triggering toxic innate immune responses. Teams at Massachusetts General Hospital (Ben Kleinstiver et al.) and collaborators described circular single‑stranded DNA donors with short double‑stranded regions that evade cGAS sensing and remain compatible with recombinase machinery; results were reported in Nature and accompanying preprints. The lead finding shows non‑viral, LNP‑delivered integrations in mouse liver with survival where conventional double‑stranded donors caused fatal immune reactions. The work provides a practical route to write gene‑sized payloads at therapeutic scales while maintaining recombinase compatibility, a key step toward generalizable genomic medicines that treat many mutation types within a gene. Investigators emphasize the approach—named INSTALL in one report—reduces cytosolic DNA sensing by minimizing exposed dsDNA length, enabling kilobase integrations via lipid nanoparticle delivery in vivo. Methods and safety readouts indicate a path to expand from single‑patient base editing to broader, scalable gene‑replacement strategies.