Data from: Which specimens from a museum collection will yield DNA barcodes? A time series study of spiders in alcohol

We report initial results from an ongoing effort to build a library of DNA barcode sequences for Dutch spiders and investigate the utility of museum collections as a source of specimens for barcoding spiders. Source material for the library comes from a combination of specimens freshly collected in the field specifically for this project and museum specimens collected in the past. For the museum specimens, we focus on 31 species that have been frequently collected over the past several decades. A series of progressively older specimens representing these 31 species were selected for DNA barcoding. Based on the pattern of sequencing successes and failures, we find that smaller-bodied species expire before larger-bodied species as tissue sources for single-PCR standard DNA barcoding. Body size and age of oldest successful DNA barcode are significantly correlated after factoring out phylogenetic effects using independent contrasts analysis. We found some evidence that extracted DNA concentration is correlated with body size and inversely correlated with time since collection, but these relationships are neither strong nor consistent. DNA was extracted from all specimens using standard destructive techniques involving the removal and grinding of tissue. A subset of specimens was selected to evaluate nondestructive extraction. Nondestructive extractions significantly extended the DNA barcoding shelf life of museum specimens, especially small-bodied species, and yielded higher DNA concentrations compared to destructive extractions. All primary data are publically available through a Dryad archive and the Barcode of Life database.

本研究报道了一项正在推进的构建荷兰蜘蛛DNA条形码序列（DNA barcode sequences）库的工作的初步结果，并探讨了博物馆馆藏标本（museum collections）作为蜘蛛条形码测序标本来源的应用价值。该序列库的源材料包含两类标本：一是为本项目专门在野外新鲜采集的标本，二是过往收藏的馆藏标本。针对馆藏标本，本研究选取了过去数十年间频繁采集到的31个物种，并挑选了代表这31个物种的一系列年代跨度逐渐增大的标本用于DNA条形码测序。根据测序成功与失败的分布模式，我们发现：采用单重聚合酶链式反应（single-PCR）标准DNA条形码测序方法时，体型较小的物种作为组织来源的有效保存时限早于体型较大的物种。通过独立对比分析（independent contrasts analysis）排除系统发育效应的影响后，物种体型与首个成功获得DNA条形码的标本的采集年代呈显著相关关系。本研究发现部分证据表明：提取的DNA浓度与物种体型呈正相关，与标本采集后的存放时间呈负相关，但上述关联既不强烈也不具备一致性。所有标本均采用标准破坏性提取技术进行DNA提取，该方法需切除并研磨部分组织样本。本研究选取了一部分标本以评估非破坏性提取方法。相较于破坏性提取方法，非破坏性提取方法可显著延长馆藏标本的DNA条形码测序有效保存期限，尤其对体型较小的物种效果更为显著，且所得DNA浓度更高。所有原始数据均可通过Dryad数字仓储（Dryad archive）与生命条形码数据库（Barcode of Life database）公开获取。