Supporting data for "Patterns of aDNA Damage Through Time and Environments - lessons from herbarium specimens"

This dataset comprises ancient DNA (aDNA) damage metrics derived from 573 herbarium specimens spanning two plant genera (<i>Hordeum</i> and <i>Oryza</i>), six species, and 220 years of collection history (1797-2017). Specimens were sourced from seven major herbaria across Europe and North America, representing diverse geographic origins from temperate Europe and the Middle East (<i>Hordeum</i>) to tropical and subtropical regions of the Americas and Southeast Asia (<i>Oryza</i>). <br> All samples underwent standardized laboratory processing using established aDNA protocols, including DNA extraction, library preparation, and low-coverage shotgun sequencing. Bioinformatic analysis followed the Latorre et al. (2020) plant aDNA pipeline, generating four key damage metrics: endogenous DNA fraction, fragment length distributions, damage fraction per site (λ), and 5' cytosine deamination frequencies. <br> The dataset addresses the critical need for large-scale, standardized aDNA preservation studies by providing the first comprehensive analysis of herbarium specimen DNA degradation across multiple species, geographic regions, and temporal scales. This resource enables investigation of temporal degradation processes, environmental influences on DNA preservation, genus-specific damage patterns, and the impact of museum storage conditions. The standardized methodology and global scope make this dataset valuable for ancient DNA researchers, museum curators developing preservation strategies, and scientists studying DNA degradation mechanisms in biological collections.