Central Conserved Sequence Block Research Articles

The complete mitochondrial genome of Schizothorax eurystomus Kessler, 1872 (Cypriniformes, Cyprinidae)

Schizothorax eurystomus, Kessler 1872 is a unique economic fish in Xinjiang, China that is rarely seen in the market. Next-generation sequencing (NGS) was used to determine the complete mitochondrial genome of S. eurystomus collected from the Yarkand River in Xinjiang. The results showed that the mitochondrial genome is a circular, 16,488-bp-long nucleotide with the typical vertebrate genome structure of 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and a control region. The termination-associated sequence (TAS), central conserved sequence block (CSB), and conserved sequence block were detected in the control region. Phylogenetic analysis placed S. eurystomus in a fully supported clade with S. biddulphi, and that clade was sister to S. yunnanensis. To our knowledge, this is the first study on the complete mitochondrial genome of S. eurystomus from the Yarkand River in Xinjiang, and it provides baseline genetic information for future studies.

The complete mitochondrial genome of the half-fin anchovy, Setipinna tenuifilis (Valenciennes, 1848)

The complete mitochondrial genome of the half-fin anchovy, Setipinna tenuifilis collected from Yellow and Bohai Seas was determined by next-generation sequencing. The mitogenome is a circular molecule 16,668 bp in length, including the typical structure of 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and a control region. The termination-associated sequence (TAS), central conserved sequence block (CSB) and CSB are detected in the control region. The gene contents of the mitogenome are identical to those observed in most bony fishes.

The complete mitochondrial genome of the spiny red gurnard Chelidonichthys spinosus McClelland, 1844 (Scorpaeniformes: Triglidae)

The spiny red gurnard, Chelidonichthys spinosus is a common marine economic fish species along the coast of China. In the present study, the complete mitochondrial genome of spiny red gurnard collected from the Yangtze Estuary was determined by next-generation sequencing (NGS). The mitogenome is a circular nucleotide 16,466 bp in length and has the typical vertebrate genome structure of 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and two control regions (Origin of Heavy chain and Origin of Light chain). The termination associated sequence (TAS), the central conserved sequence block (central CSB), and the conserved sequence block (CSB) were detected in the control region. Phylogenetic analysis of C. spinosus places in a fully supported clade with C. kumu in a sister position to Eutrigla gurnardus. The complete mitochondrial genome sequence of the spiny red gurnard provides baseline genetic information for future studies on the molecular systematics and phylogeny of bony fishes in the Triglidae.

Sequencing and characterisation of complete mitogenome DNA for Rasbora sarawakensis (Cypriniformes: Cyprinidae: Rasbora) with phylogenetic consideration

The Blueline Rasbora (Rasbora sarawakensis) is a small ray-finned fish categorized under the genus Rasbora in the Cyprinidae family. In this study, the complete mitogenome sequence of R. sarawakensis was sequenced using four primers targeting overlapping regions. The mitogenome is 16,709 bp in size, accommodating 22 transfer RNA genes, 13 protein-coding genes, two ribosomal RNA genes and a putative control region. Identical gene organisation was detected between this species and other genus counterparts. The heavy strand houses 28 genes while the light strand stores the other nine genes. Most protein-coding genes employ ATG as start codon, excluding COI gene, which utilizes GTG instead. The central conserved sequence blocks (CSB-F, CSB-E and CSB-D), variable sequence blocks (CSB-3, CSB-2 and CSB-1) as well as the terminal associated sequence (TAS) are conserved in the control region. The maximum likelihood phylogenetic tree revealed the divergence of R. sarawakensis from the basal region of the Rasbora clade, where its evolutionary relationships with R. maculatus and R. pauciperforata are poorly resolved as indicated by the low bootstrap values. This work acts as steppingstone towards further molecular evolution and population genetics studies of Rasbora genus in future.

Sequencing and characterization of complete mitogenome DNA of Rasbora tornieri (Cypriniformes: Cyprinidae: Rasbora) and its evolutionary significance

The yellowtail rasbora (Rasbora tornieri) is a miniature ray-finned fish categorized under the genus Rasbora in the family of Cyprinidae. In this study, a complete mitogenome sequence of R. tornieri was sequenced using four primers targeting two halves of the mitogenome with overlapping flanking regions. The size of mitogenome was 16,573 bp, housing 22 transfer RNA genes, 13 protein-coding genes, two ribosomal RNA genes and a putative control region. Identical gene organization was detected between this species and other members of Rasbora genus. The heavy strand encompassed 28 genes while the light strand accommodated the other nine genes. Most protein-coding genes execute ATG as start codon, excluding COI and ND3 genes, which utilized GTG instead. The central conserved sequence blocks (CSB-E, CSB-F and CSB-D), variable sequence blocks (CSB-1, CSB-3 and CSB-2) as well as the terminal associated sequence (TAS) were conserved within the control region. The maximum likelihood phylogenetic family tree revealed the divergence of R. tornieri from the basal region of the Rasbora clade, where its evolutionary relationships with other Rasbora members are poorly resolved as indicated by the low bootstrap values. This work acts as window for further population genetics and molecular evolution studies of Rasbora genus in future.

Sequencing and Characterisation of Complete Mitochondrial DNA Genome for Trigonopoma pauciperforatum (Cypriniformes: Cyprinidae: Danioninae) with Phylogenetic Consideration.

The Trigonopoma pauciperforatum or the redstripe rasbora is a cyprinid commonly found in marshes and swampy areas with slight acidic tannin-stained water in the tropics. In this study, the complete mitogenome sequence of T. pauciperforatum was first amplified in two parts using two pairs of overlapping primers and then sequenced. The size of the mitogenome is 16,707 bp, encompassing 22 transfer RNA genes, 13 protein-coding genes, two ribosomal RNA genes and a putative control region. Identical gene organisation was detected between this species and other family members. The heavy strand accommodates 28 genes while the light strand houses the remaining nine genes. Most protein-coding genes utilise ATG as start codon except for COI gene which uses GTG instead. The terminal associated sequence (TAS), central conserved sequence block (CSB-F, CSB-D and CSB-E) as well as variable sequence block (CSB-1, CSB-2 and CSB-3) are conserved in the control region. The maximum likelihood phylogenetic tree revealed the divergence of T. pauciperforatum from the basal region of the major clade, where its evolutionary relationships with Boraras maculatus, Rasbora cephalotaenia and R. daniconius are poorly resolved as suggested by the low bootstrap values. This work contributes towards the genetic resource enrichment for peat swamp conservation and comprehensive in-depth comparisons across other phylogenetic researches done on the Rasbora-related genus.

Particular gene order and complete mitochondrial genome of Parupeneus chrysopleuron (Perciformes, Mullidae)

Parupeneus chrysopleuron were under threat of climate change and unregulated fishing. For protecting the fish, complete mitochondrial genome (mitogenome) of P. chrysopleuron was firstly determined. The mitogenome is 17,397 nucleotides, including 38 genes. The gene arrangement of the P. chrysopleuron mitogenome is different from most of bony fishes. Investigating the mitochondrial gene arrangement pattern found that the tRNAIle and tRNAGln, followed by tRNAMe. Observing four notable non-coding regions, a non-coding region of 814 bp was identified as control region based on its location and central conserved sequence blocks (CSB-1 and CSB-2) were recognized.

Sequencing and Characterisation of Complete Mitogenome DNA for Rasbora hobelmani (Cyprinidae) with Phylogenetic Consideration

The Kottelat rasbora Rasbora hobelmani is a small ray-finned fish categorized under the genus Rasbora in the Cyprinidae family. In this study, the complete mitogenome sequence of R. hobelmani was sequenced using two pairs of primers covering overlapping regions. The mitogenome is 16 541 bp in length, housing 22 transfer RNA genes, 13 protein-coding genes, two ribosomal RNA genes and one putative control region. Identical gene organisation was spotted between this species and other Rasbora genus members. The heavy strand contains 28 genes while the light strand contains the remaining nine genes. Most protein-coding genes employ ATG as start codon, except for the COI gene, which exploits GTG instead. The central conserved sequence blocks (CSB-F, CSB-E and CSB-D), variable sequence blocks (CSB-3, CSB-2 and CSB-1) as well as the terminal associated sequence (TAS) are conserved in the control region. The maximum likelihood phylogenetic tree revealed the close phylogeny of R. hobelmani with R. sumatrana, R. aprotaenia, R. lateristriata and R. steineri with bootstrap value of at least 99%. This work acts as milestone towards future evolution and population genetics studies of this species as well as the Rasbora genus.

Sequencing and characterization of complete mitogenome DNA for Rasbora myersi (Cypriniformes: Cyprinidae: Rasbora) and its evolutionary significance

The Seluang fish (Rasbora myersi) is a small ray-finned fish categorized under the genus Rasbora in the Cyprinidae family. In this study, the complete mitogenome sequence of R. myersi was sequenced using two primer pairs targeting overlapping regions. The mitogenome is 16,581 bp in length, encompassing 22 transfer RNA genes, 13 protein-coding genes, two ribosomal RNA genes and a putative control region. Identical gene organisation was observed between this species and other genus counterparts. The heavy strand accommodates 28 genes while the light strand houses the other nine genes. Most protein-coding genes utilize ATG as start codon, excluding COI gene, which employs GTG instead. The central conserved sequence blocks (CSB-F, CSB-E and CSB-D), variable sequence blocks (CSB-3, CSB-2 and CSB-1) as well as the terminal associated sequence (TAS) are conserved within the control region. The R. myersi formed a trio with R. borapetensis and R. argyrotaenia in a moderately strong clade with bootstrap value of 86. This work acts as essential gateway towards further molecular evolution and population genetics studies of the Rasbora genus in future.

The Complete Mitochondrial Genome of Terapon jarbua (Centrarchiformes: Terapontidae) and Comparative Analysis of the Control Region among Eight Centrarchiformes Species

In this article, we determined and described the complete mitochondrial genome of Terapon jarbua, which is 16 664 bp in length, containing 13 protein-coding genes, two rRNA genes, 22 tRNA genes, one origin of replication on the light-strand (OL), and a putative control region (CR). The gene order and the base composition of T. jarbua mitogenome are similar to that of most other vertebrates. The overall base composition is 27.5% A, 26.0% T, 29.9% C, 16.6% G, respectively, with a slight AT bias (53.5%). All the protein-coding genes use the initiation codon ATG except COI use GTG. Most of them have TAA or TAG as the stop codon, except COII and ND4 use AGA, COIII and Cyt b use an incomplete stop codon TA and T, respectively. In order to further explore the structure of CR in Centrarchiformes, eight CR sequences from representative species were compared. Like that of other teleosts, the CR of the Centrarchiformes is also partitioned into three domains, including the termination associated sequence (TAS), the central conserved sequence blocks (CSB-E, D, B and A), and the conserved sequence blocks (CSB-2 and 3). We hope these results will provide consensus sequences of the conserved units of the CR in Centrarchiformes genomes, as well as useful molecular information for phylogenetic studies of Centrarchiformes.

Complete mitochondrial genome of the Pleuronichthys lighti (Pleuronectiformes, Pleuronectidae) with phylogenetic consideration

Mitochondrial genome has been used to shed light on many fields of both basic and applied research, including the study of molecular evolution. The complete mitochondrial genome sequence of 17368 bp nucleotides from the Pleuronichthys lighti was determined. It was a circular double-stranded DNA molecule with identical set of 22 transfer RNA genes, 2 ribosomal RNA genes, 13 protein-coding genes as well as a non-coding control region. Stand asymmetry in the nucleotide composition was reflected in the codon usage of genes oriented in opposite directions. In the control region, we identified the extended termination associated sequence domain, the central conserved sequence block domain and the conserved sequence block domain, and two complete repeat region. They were “TTACAATA” and “TGTTGTAA”, respectively. All known 12 mitochondrial genomes of Pleuronectinae fishes were downloaded and analyzed; there were 5570 variable sites in the consensus sequences of 15241 base pairs, calculation of total sites were 35.5%. The highest sequence divergence was 50% (ATP8) and the Kimura-2-parameter genetic distance was 0.235 (ND6), whereas the COIII had the lowest sequence divergence (28.8%) and genetic distance (0.128); the protein coding genes were mainly acted by purifying selection which was detected by selection tests. Analysis of confidence and the information content for per nucleotide revealed ND5, ATP6, COI and ND4 genes were suitable molecular markers for phylogenetic study of Pleuronectinae fishes. Phylogenetic analysis using Bayesian computational algorithms based on COI genes provided support for the taxonomic status of P. lighti, which was consistent with the traditional taxonomy.

Characteristics and phylogenetic analysis of the complete mitochondrial genome of Lagocephalus inermis (Tetraodontiformes; Tetraodontidae)

Lagocephalus inermis is at a high risk of extinction and is listed in the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. To better protect this species, the complete mitochondrial genome (mitogenome) of L. inermis was first determined in this study. The mitogenome of L. inermis is 16,493 nucleotides, comprising 13 protein-coding genes, 2 ribosomal RNA genes, 22 tRNA genes, and 2 main non-coding regions. The overall base composition is T 24.9%, C 31.0%, A 27.7%, and G 16.4%, with a slight A + T bias of 52.6%. In addition, the mitogenome of L. inermis is similar to most bony fishes. The central conserved sequence blocks (CSB-1, CSB-2, and CSB-3) and the core sequence (ACATATATGT) of terminal-associated sequences were recognized in the control region. Moreover, phylogenetic analysis showed that L. inermis clustered in a clade and formed a sister relationship with other species belonging to Lagocephalus.

The complete mitochondrial genome of Thryssa kammalensis (Clupeiformes: Engraulidae)

In this study, the complete mitochondrial genome (mitogenome) sequence of Thryssa kammalensis has been determined by long polymerase chain reaction and primer walking methods. The mitogenome is a circular molecule of 16 968 bp in length and contains 37 mitochondrial genes including 13 protein-coding genes, two ribosomal RNA (rRNA), 22 transfer RNA (tRNA) and a control region as other bony fishes. Within the control region, we identified the termination-associated sequence (TAS) domain, the central conserved sequence block domains (CSB-F, CSB-E and CSB-D) and the conserved sequence block domains (CSB-1, CSB-2 and CSB-3). There are eight copies of tandem repeats of 38 bp in the control region, which contain TAS.

Complete mitochondrial genome of black-banded trevally (Seriolina nigrofasciata): Genome characterization and phylogenetic considerations

The black-banded trevally (Seriolina nigrofasciata) is a species of the family Carangidae and the only known member of genus Seriolina. To understand the phylogenetic relationship of black-banded trevally in teleost, we first determined the complete mitochondrial genome of black-banded trevally. The entire mitochondrial genome of black-banded trevally is 16 531 bp in length, containing 13 protein-coding genes and 2 ribosomal RNA genes (rRNA), 22 transfer RNA genes (tRNAs), and 2 main non-coding regions. The overall base composition is T 25.8%, C 30.0%, A 26.7%, and G 17.5%. The gene arrangement, base composition, and tRNA structures of black-banded trevally are consistent with those of other teleost. Two of the central conserved sequence blocks (CSB-2 and CSB-3) were identified and the core sequence (TACATGTATGTA) of terminal-associated sequences was recognized in the control region. Meanwhile, the conserved motif 5′-GCCGG-3′ was identified in the origin of light-strand replication of black-banded trevally. The complete mitochondrial genome of black-banded trevally was used to construct phylogenetic tree, which shows that black-banded trevally is clustered with the fishes of the genus Seriola. We expect that the availability of the mitochondrial genome of black-banded trevally will facilitate the further investigations of molecular systematic and phylogenetic analysis of the Carangidae.

Complete mitochondrial DNA sequence of the endangered fish (Bahaba taipingensis): Mitogenome characterization and phylogenetic implications.

To understand the systematic status of Bahaba taipingensis within Sciaenidae, the complete mitochondrial genome (mitogenome) sequence of Chinese bahaba has recently been determined by long PCR and primer walking methods. The complete mitochondrial genome is 16500 bp in length and contains 37 mitochondrial genes (13 protein-coding genes, 2 ribosomal RNA genes and 22 transfer RNA genes) as well as a control region (CR) as other bony fishes. Within the control region, we identified the extended termination associated sequence domain (ETAS), the central conserved sequence block domain (CSB-D, SCB-E and CSB-F) and the conserved sequence block domain (CSB-1, CSB-2 and CSB-3). Phylogenetic analyses revealed that Bahaba taipingensis is more closely related to Pseudosciaeniae than Argyrosominae and Sciaeninae. Additionally, Bahaba taipingensis is the sister taxon of Miichthys miiuy, and those two are sister to Collichthys plus Larimichthys.

Characteristics and phylogenetic analysis of the complete mitochondrial genome of Cheilodactylus quadricornis (Perciformes, Cheilodactylidae)

The complete mitochondrial genome of the Cheilodactylus quadricornis was firstly determined in the present study. The mitochondrial genome of C. quadricornis is 16 521 nucleotides, comprising 13 protein-coding genes and 2 ribosomal RNA genes, 22 tRNA genes and 2 main non-coding regions (the control region and the origin of the light-strand replication). The overall base composition was T, 26.3%; C, 29.6%; A, 27.8% and G, 16.3%. The gene arrangement, base composition, and tRNA structures of the complete mitochondrial genome of C. quadricornis is similar to other teleosts. Only two central conserved sequence blocks (CSB-2 and CSB-3) were identified in the control region. In addition, the conserved motif 5′-GCCGG-3′ was identified in the origin of light-strand replication of C. quadricornis. The complete mitochondrial genome of C. quadricornis was used to construct phylogenetic tree, which shows that C. quadricornis and C. variegatus clustered in a clade and formed a sister relationship. This mitogenome sequence data would play an important role in population genetics and phylogenetic analysis of the Cheilodactylidae.

The first complete mitochondrial genome of Serranidae sp. (Percoidea, Serranidae) and phylogenetic analysis based on Bayesian

In the present study, the complete mitochondrial genome of Serranidae sp. was determined first. The entire mitochondrial genome of Serranidae sp. is 16 512 bp in length, containing 13 protein-coding genes and 2 ribosomal RNA genes (rRNA), 22 transfer RNA genes (tRNA) and 2 main non-coding regions (the control region and the origin of the light-strand replication). The gene arrangement, base composition and tRNA structures of Serranidae sp. are similar to most of the bony fishes. The central conserved sequence blocks (CSB-1, CSB-2, and CSB-3) and the core sequence (ACATATATGT) of terminal-associated sequences were recognized in the control region. Meanwhile, the conserved motif 5′-GCCGG-3′ was identified in the origin of light-strand replication of Serranidae sp. Phylogenetic tree, which is constructed based on the complete mitochondrial genome sequences of Serranidae sp., shows that Serranidae sp. is clustered with the fishes of the family Pentacerotidae. We expect that the mitochondrial genome of Serranidae sp. would play a key role in phylogenetic analysis of Serranidae.

Complete mitochondrial genome of banjofish (Banjos banjos): genome characterization and phylogenetic analysis

The banjofish (Banjos banjos) is the only species in the monotypic genus Banjos and in the family Banjosidae. To understand the phylogenetic relationship of banjofish in teleost, we firstly determined the complete mitochondrial genome of banjofish. The entire mitochondrial genome of banjofish is 16 485 bp in length, including 13 protein-coding genes and 2 ribosomal RNA genes (rRNA), 22 transfer RNA genes (tRNA) and a control region (CR). The overall base composition is T, 26.2%; C, 29.2%; A, 28.6% and G, 16.0%. The central conserved sequence blocks (CSB) were identified and the core sequence (ACATATATGT) of terminal-associated sequences was recognized in the control region. The gene arrangement, base composition, and tRNA structures of the complete mitochondrial genome of banjofish is consistent with those of other teleost. The complete mitochondrial genome of banjofish was used to construct phylogenetic tree, which shows that banjofish is clustered with the fishes of the family Histiopteridae. We expect that the availability of mitochondrial genome of banjofish will facilitate the further investigations of the taxonomic resolution, biogeography and molecular systematic.

The complete mitochondrial genome of Sillago sihama (Perciformes: Sillaginidae)

In this study, the complete mitochondrial genome (mitogenome) sequence of Sillago sihama has been determined by long polymerase chain reaction and primer walking methods. The complete mitochondrial genome is a circular molecule of 17 003 bp in length and contains 37 mitochondrial genes and a control region. Within the control region, we identified the variable number tandem repeats, as well as the termination-associated sequence domain (TAS), the central conserved sequence block domains (CSB-F∼CSB-A) and the conserved sequence block domains (CSB-1, CSB-2, and CSB-3).

Mitochondrial DNA control region of three mackerels, genus Rastrelliger: structure, molecular diversity and phylogenetic relationship

The complete mitochondrial control regions (CR) of three mackerels (Rastrelliger spp.) were examined and analyzed. The CR contained three domains, in which three termination-associated sequences (TAS-I, TAS-II and TAS-III), two central conserved sequence blocks (CSB-E, CSB-D), three conserved sequence blocks (CSB-I, CSB-II, and CSB-III) and a putative promoter were detected. Molecular indices analyses of the aligned complete CR sequences showed high level of haplotype diversities and genetic divergences among the three species. The intraspecific divergence among species of this genus ranked from 0.25% to 1.62% and interspecific divergence from 1.90% to 4.30%. The phylogenetic tree shows monophyly with R. brachysoma as a basal species of Rastrelliger. Applying the average divergence rate for fish control regions, the results suggest that the time of separation among Rastrelligers could have occurred in the middle Pleistocene era.