David Liu’s team at Harvard has advanced genome editing with twin prime editing, expanding the editing length capacity to 100 base pairs and improving safety over traditional CRISPR approaches. This technology, which pairs a nickase enzyme with reverse transcriptase and dual prime editing guide RNAs, enables precise nucleotide insertions, deletions, and replacements without double-stranded DNA breaks. Despite remaining risks of off-target mutations, prime editing holds promise for treating complex genetic diseases like Huntington's and inherited retinal degeneration, as demonstrated by successful in vivo corrections in mouse models.