Identifying Canadian Freshwater Fishes through DNA Barcodes
Date
2008-06
Authors
Hubert, Nicolas
Hanner, Robert
Holm, Erling
Mandrak, Nicholas E.
Taylor, Eric
Burridge, Mary
Watkinson, Douglas
Dumont, Pierre
Curry, Allen
Bentzen, Paul
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Abstract
Background: DNA barcoding aims to provide an efficient method for species-level identifications
using an array of species specific molecular tags derived from the 59 region of the mitochondrial
cytochrome c oxidase I (COI) gene. The efficiency of the method hinges on the degree of sequence
divergence among species and species-level identifications are relatively straightforward when the
average genetic distance among individuals within a species does not exceed the average genetic
distance between sister species. Fishes constitute a highly diverse group of vertebrates that
exhibit deep phenotypic changes during development. In this context, the identification of fish
species is challenging and DNA barcoding provide new perspectives in ecology and systematics of
fishes. Here we examined the degree to which DNA barcoding discriminate freshwater fish species from
the well-known Canadian fauna, which currently encompasses nearly 200 species, some which are of
high economic value like salmons and sturgeons. Methodology/Principal Findings: We bi-directionally
sequenced the standard 652 bp "barcode'' region of COI for 1360 individuals
belonging to 190 of the 203 Canadian freshwater fish species (95%). Most species were represented by
multiple individuals (7.6 on average), the majority of which were retained as voucher specimens. The
average genetic distance was 27 fold higher between species than within species, as K2P distance
estimates averaged 8.3% among congeners and only 0.3% among concpecifics. However, shared
polymorphism between sister-species was detected in 15 species (8% of the cases). The distribution
of K2P distance between individuals and species overlapped and identifications were only possible to
species group using DNA barcodes in these cases. Conversely, deep hidden genetic divergence was
revealed within two species, suggesting the presence of cryptic species. Conclusions/Significance:
The present study evidenced that freshwater fish species can be efficiently identified through the
use of DNA barcoding, especially the species complex of small-sized species, and that the present
COI library can be used for subsequent applications in ecology and systematics.
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Citation
Hubert, Nicolas, Robert Hanner, Erling Holm, Nicholas E. Mandrak, et al. 2008. "Identifying Canadian Freshwater Fishes through DNA Barcodes." Plos One 3(6): 2490-e2490. doi:10.1371/journal.pone.0002490