Recovering Historical eDNA From Museum-Preserved Filter Feeders via Non-Destructive Metabarcoding.

Recent technical advances have significantly enhanced the value of museum specimens for molecular research, with metagenomic and metabarcoding approaches expanding further the utility of museum collections. However, given the finite number of specimens, there is a critical need to move past destructive DNA extraction approaches and to explore non-destructive techniques. In this proof-of-concept study, we evaluated the feasibility of extracting historical eDNA from the ethanol preservative used to store museum specimens. We compared a variety of extraction methods (centrifugation, evaporation, filtration, and precipitation) using ten replicate samples per treatment for statistical analyses. To assess potential differences in preservative-derived eDNA recovery across different filter-feeding taxonomic groups, we included a bryozoan, a demosponge, and a glass sponge. Comparative analyses with tissue biopsies revealed that 10 mL ethanol filtration performed equal to or, in some instances, outperformed tissue biopsies for all three specimens when examining the historical eDNA of Antarctic fish using a 16S rRNA metabarcoding approach, both for the number of species detected (α-diversity) and community characterisation (β-diversity). This initial study demonstrates the potential of ethanol preservative as a valuable, non-destructive source of historical eDNA from museum-stored filter-feeding specimens. These findings highlight the viability of non-destructive sampling for molecular research on museum collections, preserving specimen integrity while enabling biodiversity assessments. Further refinement of non-destructive eDNA extraction could expand its applicability across taxa, collection types, and preservation methods, ensuring the long-term sustainability of museum-based genomic, metagenomic, and metabarcoding research.