Appraisal of the entire mitochondrial genome for DNA barcoding in birds

Document Type: Research Paper

Authors

1 Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran

2 1. Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran 2. Research Department of Zoological Innovations, Institute of Applied Zoology, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Iran

Abstract

DNA barcoding based on a standardized region of 648 base pairs of mitochondrial DNA
sequences from Cytochrome C Oxidase 1 (COX1) is proposed for animal species identification.
Recent studies suggested that DNA barcoding has been effective for identifying 94% of bird
species. The proposed threshold of 10 times the average intraspecific variation could be used for
the identification and delimitation of new species. As a different part of the mitochondrial DNA
evolves at various mutation rates, they show a variety of capabilities to distinguish taxa to
species level. In order to compare the efficiency of protein-coding genes (PCGs) in birds, the
complete genome of 310 birds, including 12 mitochondrial genes (except ND6) and barcoding
the region of COX1, were examined. We concentrated on the intra- and inter-specific variations
and the degree of mutational saturation as criteria for our evaluations. Some genes like ATP8,
ND2 and ND5 showed the greatest divergence in intra- and inter-specific variations. The
overlap between intra- and inter-specific variability for all genes is still troublesome. Our results
may have been influenced by the sample size because our data were not representative of all
bird species. More additional taxa may shed light more on DNA barcoding candidate genes.
 

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