Data from: Influence of killing method on Lepidoptera DNA barcode recovery

The global DNA barcoding initiative has revolutionized the field of biodiversity research. Such large-scale sequencing projects require the collection of large numbers of specimens, which need to be killed and preserved in a way that is both DNA-friendly and which will keep voucher specimens in good condition for later study. Factors such as time since collection, correct storage (exposure to free water and heat) and DNA extraction protocol are known to play a role in the success of downstream molecular applications. Limited data are available on the most efficient, DNA-friendly protocol for killing. In this study, we evaluate the quality of DNA barcode (cytochrome oxidase I) sequences amplified from DNA extracted from specimens collected using three different killing methods (ethyl acetate, cyanide and freezing). Previous studies have suggested that chemicals, such as ethyl acetate and formaldehyde, degraded DNA and as such may not be appropriate for the collection of insects for DNA-based research. All Lepidoptera collected produced DNA barcodes of good quality, and our study found no clear difference in nucleotide signal strength, probability of incorrect base calling and phylogenetic utility among the three different treatment groups. Our findings suggest that ethyl acetate, cyanide and freezing can all be used to collect specimens for DNA analysis.

全球DNA条形码计划（DNA barcoding initiative）彻底革新了生物多样性研究领域。此类大规模测序项目需要采集大量标本，且需以既能保证DNA完整性、又能将凭证标本（voucher specimens）妥善保存以供后续研究的方式进行处死与保存。已有研究表明，采集后的存放时长、正确的保存方式（避免游离水与高温暴露）以及DNA提取流程（DNA extraction protocol），均会对后续分子实验的成功率产生影响。目前针对最高效且能保证DNA完整性的标本处死方法，相关研究数据仍较为有限。本研究针对采用三种不同处死方法（乙酸乙酯（ethyl acetate）、氰化物（cyanide）、冷冻法（freezing））采集的标本提取的DNA，对其扩增得到的DNA条形码（细胞色素氧化酶I，cytochrome oxidase I）序列质量进行了评估。既往研究表明，乙酸乙酯、甲醛（formaldehyde）等化学试剂会降解DNA，因此可能不适用于基于DNA研究的昆虫标本采集。本研究中所有鳞翅目（Lepidoptera）标本均可获得高质量的DNA条形码序列，且未发现三种处理组在核苷酸信号强度、碱基误判概率以及系统发育适用性方面存在显著差异。本研究结果显示，乙酸乙酯、氰化物与冷冻法均可用于标本采集以开展DNA分析。