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An update on DNA barcoding: low species coverage and numerous unidentified sequences
Shiyang Kwong1, Amrita Srivathsan1, Rudolf Meier1,2
1Department of Biological Sciences.
Cladistics : the International Journal of the Willi Hennig Society
|December 3, 2021
Summary
DNA barcoding for multicellular animals shows sparse species coverage despite significant funding. Most public DNA barcodes are not identified to species, hindering biodiversity assessment.
Area of Science:
- Genomics
- Biodiversity Science
- Bioinformatics
Background:
- The DNA barcoding initiative, established in 2003, aims to catalog species using standardized genetic markers.
- Significant funding has been invested, yet comprehensive species coverage remains a challenge.
Purpose of the Study:
- To assess the current species coverage of DNA barcoding in multicellular animals.
- To compare data availability between public repositories (GenBank) and specialized databases (BOLD).
Main Methods:
- Comparative analysis of DNA sequence data from GenBank and the Barcode of Life Database (BOLD) as of January 2012.
- Evaluation of species identification levels and data provenance for deposited sequences.
Main Results:
- GenBank contained COI sequences for approximately 60,000 species, while BOLD reported 150,000, with the discrepancy attributed to unpublished data in BOLD.
- Overall species coverage is sparse, with low growth rates and a linear accumulation curve for Metazoa.
- A significant portion (73%) of GenBank data originated from non-barcoding projects, and 74% of DNA barcodes lacked species-level identification.
Conclusions:
- Despite substantial investment, DNA barcoding coverage for multicellular animals remains limited.
- Data quality and identification accuracy in public databases present challenges for biodiversity research.
- Targeted barcoding campaigns show better coverage but still fall short of campaign goals.
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