Table 3.
Desirability | Voucher type | Description | Suitable for | Potential issues |
---|---|---|---|---|
High Low |
Primary voucher | Whole organism is preserved and deposited in a permanent collection. Vouchers can be dried, in a preservation liquid (ethanol), or frozen (e.g., biobanked tissue or cell culture vouchers). | Species that are of a suitable size for a permanent collection (taxon-specific), and can be legally and ethically collected |
• Not possible for very large/small species. • Species might be too rare to sacrifice for a voucher. • Preservation method determines possible additional future uses. |
Secondary voucher: to complement -not replace- whole organism vouchering | E-voucher: digital image taken of whole organism and of diagnostic characteristics | Small species requiring destructive sampling to obtain sufficient genetic material for a high-quality genome assembly (e.g., single-cell protist) |
• Can require specialist equipment and expertise (e.g., microscope imaging of insect genitalia). • May have limited use in taxonomic identification. • Diagnostic characteristics may not be known. |
|
Partial Voucher: tissue samples are taken, preserved, curated and stored in permanent collections. | For very large organisms (e.g., a whale), or very small (e.g., small insects), where preservation of the whole organism is not feasible. | • Body part/tissue taken may not represent diagnostic taxonomic characteristics | ||
Proxy voucher: a sample that identified as the same species to be sequenced, and was collected from the same time and location | Species that are too small for direct or partial vouchering (e.g., bryophyte) | • May not be the same as the sequenced species |