Generating high quality reference genomes from field collected specimens by optimizing preservation

Sample preservation challenges efforts to generate high-quality reference genomes or pangenomes for all 2 million+ plant and animal species. Here we compare the impacts of storage methods including solutions, temperature, and time on DNA quality and long-read sequencing quality in 10 fish and 4 plant species. We show 95 percent ethanol protects against sample degradation for fish blood (22 C, less than or equal to 6 weeks) and plant tissue (4 C, less than or equal to 3 weeks). Using Nanopore, we assemble high quality reference genomes from three fish and two plant species (contig N50: 6.5-13.8Mb; BUSCO completeness: 94.4-99.2 percent; QV: 43.8 for M. esculenta).