Blast from the past: metabarcoding analysis of formalin-preserved mesozooplankton assemblages

Historically, zooplankton samples preserved in formalin pose challenges for molecular analysis due to induced DNA alterations. This study aimed to develop an extraction method and amplification protocol for DNA metabarcoding of such samples. Pre-treated with an alkaline buffer, samples underwent amplification targeting two gene regions: nuclear 18S rRNA and mitochondrial COI, using four primer sets. Results suggest DNA metabarcoding as promising for studying historical collections, with successful amplification for both genes despite optimization needs. This method represents a significant advancement in the study of historical zooplankton communities.