DNA barcodes from century-old type specimens using next generation sequencing

Type specimens have high scientific importance because they provide the only certain connection between the application of a Linnean name and a physical specimen. Many other individuals may have been identified as a particular species, but their linkage to the taxon concept is inferential. Because type specimens are often more than a century old and have experienced conditions unfavorable for DNA preservation, success in sequence recovery has been uncertain. The present study addresses this challenge by employing next generation sequencing (NGS) to recover sequences for the barcode region of the cytochrome c oxidase 1 gene from small amounts of template DNA. DNA quality was first screened in more than 1800 century-old type specimens of Lepidoptera by attempting to recover 164bp and 94bp reads via Sanger sequencing. This analysis permitted the assignment of each specimen to one of three DNA quality categories – high (164bp sequence), medium (94bp sequence), or low (no sequence). Ten spec...模式标本（type specimens）具有极高的科学研究价值，因其是林奈式学名（Linnean name）的应用与实物标本之间唯一确凿的关联依据。尽管诸多其他个体可被鉴定为某一特定物种，但它们与该分类群（taxon）概念的关联仅为推测性的。由于模式标本的年代往往超过百年，且曾处于不利于DNA保存的环境中，其序列的成功获取长期以来均存在不确定性。本研究采用下一代测序技术（next generation sequencing, NGS），从微量模板DNA中获取细胞色素c氧化酶亚基1基因（cytochrome c oxidase 1 gene）的条形码区域序列，以攻克这一技术难题。研究团队首先通过桑格测序（Sanger sequencing）尝试获取164bp与94bp的读段，对1800余件鳞翅目（Lepidoptera）百年模式标本的DNA质量开展筛查。该分析可将每件标本划分为三类DNA质量等级——高（可获得164bp序列）、中（可获得94bp序列）或低（未获得任何序列）。共选取10份……