design: Genomic DNA was isolated from liver using the DNeasy Blood & Tissue Kit (Qiagen, #69504). DNA concentration was measured with the Qubit dsDNA BR Assay Kit (Thermo Fisher Scientific, #Q33266) and DNA integrity was assessed on an TapeStation using Genomic DNA ScreenTape (Agilent #5067-5365/5067-5366). Samples with a DNA integrity number (DIN) > 7 were selected for library preparation. Libraries were prepared for Duplex Sequencing (DS) using the Duplex Sequencing Mouse Mutagenesis Panel v2.0 (TwinStrand Biosciences, Seattle, WA). The panel targets 20 genomic regions (~48 kb total) distributed across the mouse autosomes and is designed to approximate genome-wide diversity in sequence context, GC content, chromatin state, and coding status (LeBlanc et al., 2022). For each sample, 500 ng of genomic DNA was enzymatically fragmented, end-polished, A-tailed, and ligated to Duplex Sequencing adapters with unique molecular identifiers (UMIs). Final libraries were quantified with the Qubit dsDNA High Sensitivity Assay (Thermo Fisher Scientific, #Q33231), and average fragment size was assessed on a TapeStation using High Sensitivity D1000 ScreenTape (Agilent #5067-5584/5067-5585). Libraries were pooled and submitted to Psomagen (Rockville, MD) for sequencing.