Evaluating DNA cross-contamination risk using different tissue sampling procedures on board fishing and research vessels

Abstract Sample cross-contamination remains a pervasive issue in genetics and genomics. With growing reliance on molecular methods for managing marine resources, the need to ensure integrity of tissue samples that underpin these has never been more pressing. We conducted an experiment wild-caught bigeye tuna (Thunnus obesus) assess risk under seven at-sea laboratory-based sampling treatments. The six treatments (T1–T6) differ equipment, cleaning, storage procedures. Combining observed heterozygosity (Ho) relatedness coefficients (r) flag cross-contamination, T2–T6 proved effective at mitigating contamination risk. Each exhibited significantly smaller mean Ho less variability compared with intentionally contaminated T1 treatment. In T2-T6, no flagged as based outlier thresholds elevated r were traced point sea. Laboratory-based subsampling (T7) also led smaller, variable values T1, suggesting recovery onboard, or those unknown provenance, is possible. show simple adjustments current protocols dramatically reduce downstream genetic analyses tunas potentially other species fisheries.