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荷兰蜘蛛DNA条形码(DNA barcode)序列库构建工作的初步结果，并探讨了博物馆馆藏标本作为蜘蛛条形码研究样本来源的应用价值。该序列库的样本来源分为两类：一是为本项目专门在野外新近采集的标本，二是既往征集入藏的博物馆馆藏标本。针对博物馆馆藏标本，本研究选取了过去数十年间频繁采集到的31个蜘蛛物种，并针对这31个物种分别选取了年代跨度渐增的系列标本开展DNA条形码测序。基于测序成功与失败的分布模式，本研究发现：采用单聚合酶链反应(PCR)标准DNA条形码流程获取组织样本时，体型较小的物种比体型较大的物种更早丧失可用于测序的有效组织。通过独立对比分析(independent contrasts analysis)去除系统发育效应后，物种体型与成功获得DNA条形码的最老标本的采集年代之间存在显著相关性。本研究发现部分证据表明，提取得到的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，但上述相关性既不强也不稳定。所有标本均采用标准破坏性提取方法处理：即通过移除并研磨组织来提取DNA。此外，本研究选取了部分标本用于评估非破坏性提取方法的效果。相较于破坏性提取方法，非破坏性提取方法可显著延长博物馆馆藏标本的DNA条形码可测序保存期限，尤其对体型较小的物种效果更为突出，且所得DNA浓度更高。所有原始数据均可通过Dryad数据库与生命条形码数据库(Barcode of Life database)公开获取。