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Vol. 53, 2014
Complete mitochondrial genome sequences of three rhombosoleid
fishes and comparative analyses with other flatfishes
(Pleuronectiformes)
Shu-Ying
Wang, Wei Shi, Xian-Guang Miao and Xiao-Yu Kong*
Key
Laboratory of Tropical Marine Bio-resources and Ecology, Marine
Biodiversity Collection of South China Sea, South China Sea Institute
of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
Abstract
Background: Peltorhamphus novaezeelandiae, Colistium nudipinnis, and Pelotretis flavilatus belong to the family
Rhombosoleidae of Pleuronectiformes. Their high phenotypic similarity
has provoked great differences in the number and nomenclature of the
taxa that depend primarily on morphological features. These facts have
made it necessary to develop molecular markers for taxonomy and
phylogenetic studies. In this study, the complete mitogenomes (mtDNA)
of the three rhombosoleid fishes were determined for the comparative
studies and
potential development of molecular markers in the future.
Results: The lengths of the complete mitogenome of
the three flatfishes are 16,889, 16,588, and 16,937 bp in the order
mentioned above. The difference of lengths mainly results from the
presence of tandem repeats at the 3′-end with variations of motif
length and copy number in the control regions (CR). The gene content
and arrangement is identical to that of the typical teleostean mtDNA.
Two large intergenic spacers of 28 and 18 bp were found in P. flavilatus mtDNA. The genes are
highly conserved except for the sizes of ND1 (which is 28 bp shorter than
the two others), ND5 (13 bp
longer), and tRNAGlu
(5 bp longer) in P. flavilatus
mtDNA. The symbolic structures of the CRs are observed as in other
fishes, including ETAS, CSB-F, E, D, C, B, A, G-BOX, pyrimidine tract,
and CSB2, 3.
Conclusions: Comparative genomic
analysis within rhombosoleids revealed that the mitogenomic feature of P. flavilatus was significantly
different from that of the two others. Base composition, gene
arrangement, and CR structure were carried on in the 17 mitogenomes.
Apart from gene rearrangement in two tongue soles (Cynoglossus semilaevis and Cynoglossus abbreviatus), the gene order in 15
others is identical to that of the typical fish mitogenomes. Of the 16
studied mitogenomes, 15 species (except for Zebrias zebrinus) have tandem repeats at
the 3′-, 5′-, or both 3′- and 5′-ends of the CRs. Moreover, the motif
length and copy number intraspecies or interspecies are also variable.
These phenomena fully indicate the diversity of repeats in flatfish
mtDNA and would provide useful data for studies on the structure of
mitogenomes in fishes.
Key words: Peltorhamphus novaezeelandiae; Colistium nudipinnis; Pelotretis flavilatus; mtDNA.
*Correspondence: E-mail: xykong@scsio.ac.cn
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