Evaluating the utility of cox1 for cetacean species identification
Article first published online: 17 MAR 2011
© 2011 by the Society for Marine Mammalogy Published 2011. This article is a US Government work and is in the public domain in the USA.
Marine Mammal Science
Volume 28, Issue 1, pages 37–62, January 2012
How to Cite
Viricel, A. and Rosel, P. E. (2012), Evaluating the utility of cox1 for cetacean species identification. Marine Mammal Science, 28: 37–62. doi: 10.1111/j.1748-7692.2010.00460.x
- Issue published online: 28 DEC 2011
- Article first published online: 17 MAR 2011
- Received: 26 March 2010, Accepted: 27 November 2010
- DNA barcoding;
- species identification;
- mitochondrial DNA;
- conservation genetics
The mitochondrial cytochrome c oxidase I (cox1) gene has been promoted as a universal reference gene, or barcode, to identify organisms to the species level. We evaluated whether cox1 would be appropriate to diagnose cetacean species. The 5′ end of cox1 (686 base pairs, bp) was sequenced for 46 of 86 recognized species of cetaceans. In addition, we included 105 sequences from GenBank, increasing our taxonomic coverage to 61 species. Particular focus was placed on sampling two subfamilies that contain closely related taxa: the Delphininae and the Globicephalinae. Species-specific sequences were observed for all but three taxa (Delphinus delphis, D. capensis, and Stenella coeruleoalba). Although correct assignment was seen for most species, significant overlap between intra- and interspecific variation makes cox1 an imperfect barcode for cetaceans. The efficacy of cox1 was compared to the 5′ end of the cytochrome b (cytb) gene, a mitochondrial region routinely used for cetacean species identification. Although cytb performed better than cox1 for some species, this marker could not differentiate other closely related taxa (Eubalaena spp.). Species identification for taxa not reliably identified using cox1 or cytb might be best addressed through use of multiple mitochondrial DNA fragments or other newly developed markers.