Protocols for dry <scp>DNA</scp> storage and shipment at room temperature

<jats:title>Abstract</jats:title><jats:p>The globalization of DNA barcoding will require core analytical facilities to develop cost‐effective, efficient protocols for the shipment and archival storage of <jats:styled-content style="fixed-case">DNA</jats:styled-content> extracts and <jats:styled-content style="fixed-case">PCR</jats:styled-content> products. We evaluated three dry‐state <jats:styled-content style="fixed-case">DNA</jats:styled-content> stabilization systems: commercial <jats:styled-content style="fixed-case">B</jats:styled-content>iomatrica<jats:sup>®</jats:sup> <jats:styled-content style="fixed-case">DNA</jats:styled-content>stable<jats:sup>®</jats:sup> plates, home‐made trehalose and polyvinyl alcohol (<jats:styled-content style="fixed-case">PVA</jats:styled-content>) plates on 96‐well panels of insect <jats:styled-content style="fixed-case">DNA</jats:styled-content> stored at 56 °C and at room temperature. Controls included unprotected samples that were stored dry at room temperature and at 56 °C, and diluted samples held at 4 °C and at −20 °C. <jats:styled-content style="fixed-case">PCR</jats:styled-content> and selective sequencing were performed over a 4‐year interval to test the condition of <jats:styled-content style="fixed-case">DNA</jats:styled-content> extracts. <jats:styled-content style="fixed-case">B</jats:styled-content>iomatrica<jats:sup>®</jats:sup> provided better protection of <jats:styled-content style="fixed-case">DNA</jats:styled-content> at 56 °C and at room temperature than trehalose and <jats:styled-content style="fixed-case">PVA</jats:styled-content>, especially for diluted samples. <jats:styled-content style="fixed-case">PVA</jats:styled-content> was the second best protectant after <jats:styled-content style="fixed-case">B</jats:styled-content>iomatrica<jats:sup>®</jats:sup> at room temperature, whereas trehalose was the second best protectant at 56 °C. In spite of lower <jats:styled-content style="fixed-case">PCR</jats:styled-content> success, the <jats:styled-content style="fixed-case">DNA</jats:styled-content> stored at −20 °C yielded longer sequence reads and stronger signal, indicating that temperature is a crucial factor for <jats:styled-content style="fixed-case">DNA</jats:styled-content> quality which has to be considered especially for long‐term storage. Although it is premature to advocate a transition to <jats:styled-content style="fixed-case">DNA</jats:styled-content> storage at room temperature, dry storage provides an additional layer of security for frozen samples, protecting them from degradation in the event of freezer failure. All three forms of <jats:styled-content style="fixed-case">DNA</jats:styled-content> preservation enable shipment of dry <jats:styled-content style="fixed-case">DNA</jats:styled-content> and <jats:styled-content style="fixed-case">PCR</jats:styled-content> products between barcoding facilities.</jats:p>