Proceedings of the Royal Society of London. Series B: Biological Sciences
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Barcoding animal life: cytochrome c oxidase subunit 1 divergences among closely related species

Paul D.N. Hebert

Paul D.N. Hebert

Department of Zoology, University of Guelph, Guelph, Ontario N1G 2W1, Canada

[email protected]

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,
Sujeevan Ratnasingham

Sujeevan Ratnasingham

Department of Zoology, University of Guelph, Guelph, Ontario N1G 2W1, Canada

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and
Jeremy R. de Waard

Jeremy R. de Waard

Department of Zoology, University of Guelph, Guelph, Ontario N1G 2W1, Canada

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    With millions of species and their life-stage transformations, the animal kingdom provides a challenging target for taxonomy. Recent work has suggested that a DNA-based identification system, founded on the mitochondrial gene, cytochrome c oxidase subunit 1 (COI), can aid the resolution of this diversity. While past work has validated the ability of COI sequences to diagnose species in certain taxonomic groups, the present study extends these analyses across the animal kingdom. The results indicate that sequence divergences at COI regularly enable the discrimination of closely allied species in all animal phyla except the Cnidaria. This success in species diagnosis reflects both the high rates of sequence change at COI in most animal groups and constraints on intraspecific mitochondrial DNA divergence arising, at least in part, through selective sweeps mediated via interactions with the nuclear genome.