Researchers at the Arc Institute and University of California, Berkeley have engineered RNA-guided bridge recombinases to perform massive, programmable human genome rearrangements spanning megabase lengths. The technology allows targeted insertion, deletion, and inversion of large chromosomal segments in human cells, surpassing previous gene-editing tools limited to smaller edits. This universal platform holds promise for developing novel genetic therapies addressing complex diseases by precisely rewriting extensive genomic regions.