Summary and key recommendations
DNA barcoding involves the standardised use of DNA sequences to tell species apart. This report explores the feasibility and strategic use of natural history collections for DNA barcoding and wider genomic approaches for discriminating among species. The report is based on discussions at the International Barcode of Life Conference in Guelph, Canada (August 2015) and a workshop at the Royal Botanic Garden Edinburgh, UK (September 2015), supported by further dialogue and literature surveys.
Recovery of DNA sequence data from preserved natural history collections has traditionally been hampered by DNA degradation. However, large‐scale studies have recently demonstrated effective recovery of DNA barcode data from natural history collections even using traditional Sanger sequencing approaches. Such effective access to expertly verified material in natural history collections represents a strategically important contribution to constructing a DNA barcode reference library for life on earth.
The development of new technologies focused on massively parallel short‐read sequencing is enabling a further step change in recovery of nucleotide sequences from preserved specimens. Both target‐capture methods and shotgun sequencing are resulting in rapid production of large genetic datasets from preserved museum and herbarium specimens suitable for species discrimination.
The authors of this report identified the following (non‐exhaustive) strategic priorities for DNA barcoding of natural history collections:
- Sequencing of type specimens to formalise the link between scientific names and sequences
- Targeted sequencing to fill gaps in phylogenetic coverage (e.g. genera with no sequenced
- specimens)
- DNA barcode surveys of large genera to facilitate taxonomic revisions of difficult groups
- DNA barcoding of endangered species to support enforcement of wildlife crime
- DNA barcoding of key pollinator species to enhance understanding of ecosystem service
- provision / food security
- Sequencing invasive non‐natives, pest and pathogens to support control and management
- DNA barcoding species impacting human health to support effective diagnostics and control
The selection of samples and the design of barcoding projects for natural history collections also involves important practical considerations: (a) Recently collected material typically has high resolution spatial coordinates, rich meta‐data and close links to ongoing projects. There is clear efficiency benefit to targeting efforts toward such recently collected and actively used material. (b) Sequencing type‐specimens can be extremely useful in linking names to genetic data, but this value is only realised if the regions being sequenced are diagnostic at the species level (an assumption not satisfied in e.g. many plant species). Careful attention is required to promote genetic access to type material, whilst avoiding tissue sacrifice for uninformative assays. (c) Projects using natural history collections have often focused on particular taxonomic groups or geographical areas. Addressing some of the pressing applications of DNA barcoding (e.g. diagnostics for invasive species, pests and pathogens) will require new large‐scale inter‐institutional collaborative projects drawing on expertise and samples sets with very wide phylogenetic coverage and geographical spread.
