Molecular cloning and mRNA tissue expression of thyroid hormone receptors in yellow catfish Pelteobagrus fulvidraco and Javelin goby Synechogobius hasta

Thyroid hormones (THs) play a pivotal role in many physiological functions in vertebrates, including fish. Their effects are mediated by thyroid hormone receptors (TRs), which are members of the nuclear hormone receptor superfamily. In this study, full-length cDNA sequences of TRs from yellow catfish Pelteobagrus fulvidraco and Javelin goby Synechogobius hasta were cloned and their mRNA tissue expression profiles were determined. In P. fulvidraco, the validated cDNAs encoding for TRα and TRβ were 1789 and 1848 bp in length, encoding peptides of 401 and 378 amino acid residues, respectively. In addition, a TRβ spliced variant (named P. fulvidraco-TRβv), containing a 60-bp insertion, was detected. In S. hasta, cDNAs encoding for TRαA, TRαB and TRβ were 1827, 2295 and 2258 bp in length, encoding peptides of 401, 409 and 393 amino acid residues, respectively. The phylogenetic analysis revealed that TRα and TRβ cDNAs grouped into two separate clusters with other vertebrate counterparts and two TRα sequences grouped separately, suggesting that the two TRαs derived from paralogous genes that might arise during a teleost-specific genome duplication event. All TR mRNAs were detected in various tissues sampled. The mRNA levels of both TRα and TRβ from P. fulvidraco were the highest in brain, followed by liver, and lowest in heart, intestine, muscle, gill and spleen. However, in S. hasta, TRαA, TRαB and TRβ showed the highest mRNA levels in brain and lowest in muscle. Identification and mRNA tissue expression of TR genes from P. fulvidraco and S. hasta provide an initial step towards understanding their biological roles in the two fish species.     

The first mitochondrial genome for Brahmin moths (Brahmaeidae) and implications for the higher phylogeny of Bombycoidea

Bombycoidea comprises 10 families and 4723 species, and the phylogenetic relationships among families are still in debate. In this study, we have determined the complete mitochondrial genome (mitogenome) of Brahmaea porphyria. The 15,429-bp mitogenome contains a common set of 37 mitochondrial genes including 13 protein-coding genes, 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs) and an inferred control region, and shares the conserved gene rearrangement (trnM-trnI-trnQ) in most ditrysian mitogenomes. Moreover, we analysed the secondary structure for all the tRNA genes of B. porphyria and the preference of codon usage in the PCGs of B. porphyria. The putative 373-bp control region (CR) possesses three types of conserved elements, including ATAGA, Ploy-T stretch, and microsatellite-like elements. A phylogenetic analysis among available Bombycoidea mitogenomes using the concatenated 37 mitochondrial genes appears to support the hypothesis of (Sphingidae+Bombycidae)+Saturniidae and the relatively basal phylogenetic position of Brahmaeidae within Bombycoidea.     

The complete mitochondrial genome of Plesiastrea versipora (Scleractinia,Plesiastreidae) sheds light on its phylogeny and taxonomy of the family Plesiastreidae

The genus Plesiastrea used to be a member of the traditional family Faviidae, falling into the challenging ‘Bigmessidae’ clade, and was re-established until recent molecular phylogenies published. The entire mitogenome of the symbiotic coral Plesiastrea versipora (Lamarck, 1816), the type species of the family Plesiastreidae, was sequenced. The length of the mitochondrial genome is 15,320 bp and it includes thirteen protein-coding genes (PCGs), two rRNAs and two tRNAs. The nucleotide composition of GC is 32%. We perform phylogenetic reconstruction based on maximum likelihood (ML) and Bayesian analysis(BI) using all PCGs. Our result indicates that P. versipora clusters closely with species which belong to Mussidae, Merulinidae and Lobophylliidae. Our phylogenetic analyses provide solid evidence for phylogenetic placement of P. versipora and the evolutionary relationships among different families within the traditional robust clade of Scleractinia. In addition, the mitogenome data provide useful information for further molecular systematic investigations on Plesiastreidae as well as conservation biology research of P. versipora.     

The compact mitochondrial genome of Zorotypus medoensis provides insights into phylogenetic position of Zoraptera

Background

Zoraptera, generally regarded as a member of Polyneoptera, represents one of the most enigmatic insect orders. Although phylogenetic analyses based on a wide array of morphological and/or nuclear data have been performed, the position of Zoraptera is still under debate. Mitochondrial genome (mitogenome) information is commonly considered to be preferable to reconstruct phylogenetic relationships, but no efforts have been made to incorporate it in Zorapteran phylogeny. To characterize Zoraptera mitogenome features and provide insights into its phylogenetic placement, here we sequenced, for the first time, one complete mitogenome of Zoraptera and reconstructed the phylogeny of Polyneoptera.

Results

The mitogenome of Zorotypus medoensis with an A + T content of 72.50% is composed of 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and a noncoding A + T-rich region. The gene content and arrangement are identical to those considered ancestral for insects. This mitogenome shows a number of very unusual features. First, it is very compact, comprising 14,572 bp, and is the smallest among all known polyneopteran mitogenomes. Second, both noncoding sequences and coding genes exhibit a significant decrease in size compared with those of other polyneopterans. Third, Z. medoensis mitogenome has experienced an accelerated substitution rate. Fourth, truncated secondary structures of tRNA genes occur with loss of dihydrouridine (DHU) arm in trnC, trnR, and trnS(AGN) and loss of TΨC arm in trnH and trnT. The phylogenetic analyses based on the mitogenome sequence information indicate that Zoraptera, represented by Z. medoensis, is recovered as sister to Embioptera. However, both Zoraptera and Embioptera exhibit very long branches in phylogenetic trees.

Conclusions

Characterization of Z. medoensis mitogenome contributes to our understanding of the enigmatic Zoraptera. Mitogenome data demonstrate an overall strong resolution of deep-level phylogenies of Polyneoptera but not Insecta. It is preferable to expand taxon sampling of Zoraptera and other poorly represented orders in future to break up long branches.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-1156) contains supplementary material, which is available to authorized users.     

The complete mitogenome of Parapoynx crisonalis (Walker, 1859) (Lepidoptera: Crambidae), with phylogenetic relationships amongst three acentropine larval forms

The larvae of Parapoynx crisonalis (Walker, 1859) is an important pest in China, causing significant damage on the aquatic crops. To improve the management of P. crisonalis and demonstrate the phylogenetic relationships amongst Pyraloidea, the complete mitochondrial genome (mitogenome) sequences of four aquatic pyralid moths, which belong to three acentropine larval forms – Parapoynx-type, Nymphula-type and Potamomusa-type, and twenty-three terricolous pyralids were compared. The complete mitogenome P. crisonalis, a typical parapoynx larval species, was 15,374 base pairs in length and included 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes and an A + T-rich region. The phylogenetic analysis revealed that all the aquatic acentropine moths formed a monophyletic clade with strong phylogenetic support via maximum likelihood and Bayesian methods with a bootstrap value of 100% and a posterior probability of 1.00. The Potamomusa-type was more closely related to the Nymphula-type than to the Parapoynx-type.     

Complete mitochondrial genome of the atlas moth, Attacus atlas (Lepidoptera: Saturniidae) and the phylogenetic relationship of Saturniidae species

Mitochondrial genome (mitogenome) can provide information for genomic structure as well as for phylogenetic analysis and evolutionary biology. In this study, we present the complete mitogenome of the atlas moth, Attacus atlas (Lepidoptera: Saturniidae), a well-known silk-producing and ornamental insect with the largest wing surface area of all moths. The mitogenome of A. atlas is a circular molecule of 15,282 bp long, and its nucleotide composition shows heavily biased towards As and Ts, accounting for 79.30%. This genome comprises 13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and an A + T-rich region. It is of note that this genome exhibits a slightly positive AT skew, which is different from the other known Saturniidae species. All PCGs are initiated by ATN codons, except for COI with CGA instead. Only six PCGs use a common stop codon of TAA or TAG, whereas the remaining seven use an incomplete termination codon T or TA. All tRNAs have the typical clover-leaf structure, with an exception for tRNA^Ser(AGN). The A. atlas A + T-rich region contains non-repetitive sequences, but harbors several features common to the Bombycoidea insects. The phylogenetic relationships based on Maximum Likelihood method provide a well-supported outline of Saturniidae, which is in accordance with the traditional morphological classification and recent molecular works.     

The first complete mitogenome of Picumnus innominatus (Aves,Piciformes, Picidae) and phylogenetic inference within the Picidae

The avian family Picidae, which is nearly global in distribution, contains the piculets (Picumninae and Nesoctitinae), the woodpeckers (Picinae), and the wrynecks (Jynginae). However, the phylogenetic relationships within the Picidae remain obscure for most genera. In the present study, the complete mitochondrial genome of Picumnus innominatus was determined and described, which was the first complete mitogenome reported in the Picumnus. The circular mitogenome of P. innominatus was 17,180 bp in size and consisted of 13 protein-coding genes (PCGs), 22 tRNAs, 2 rRNA genes, a control region (CR), and a noncoding region. The gene order and arrangement of the P. innominatus mitogenome were identical to other mitogenomes of the Picidae. Moreover, strikingly large tandem repeats were found in the noncoding region of the P. innominatus mitogenome, which have not yet been covered in other picid species to date. At the family level (Picidae), the highest dN/dS ratio was detected for the ND1 gene (1.38726) among 13 PCGs, indicating that positive selection was powerful for this gene. Bayesian and Maximum Likelihood phylogenetic analyses based on the combination of 12S rRNA and CYTB gene supported strongly that the Picumninae is monophyletic.     

Complete mitochondrial genome sequence of bighead croaker Collichthys niveatus (Perciformes, Sciaenidae): a mitogenomic perspective on the phylogenetic relationships of Pseudosciaeniae

The monophyly and phylogenetic relationships of Pseudosciaeniae have long been controversial. Here we describe the mitochondrial genome (mitogenome) sequence of Collichthys niveatus. It is a circular double-stranded DNA molecule of 16,450 base pairs (bp) in length with a standard set of 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes (rRNAs), 13 protein-coding genes as well as a non-coding control region. The mitogenome of C. niveatus shared common features with those of other bony fishes in terms of gene arrangement, base composition, and tRNA structures. The C. niveatus mitogenome exhibited pronounced strand-specific asymmetry in nucleotide composition, which was also reflected in the codon usage of genes oriented in opposite directions. Contrary to the typical structure of the control region, the central conserved blocks (CSB-D, -E, and -F) could not be detected in C. niveatus mitogenome. Phylogenetic analysis based on whole mitogenome sequences provided strong support for the monophyly of Pseudosciaeniae, and sister-group relationships of C. niveatus + Collichthys lucidus and Larimichthys crocea + Larimichthys polyactis, which was consistent with the traditional taxonomy. Unexpected divergence was found in two C. niveatus mitogenomes and several hypotheses were proposed to explain this observation including misidentification and introgressive hybridization between C. niveatus and L. polyactis, and polyphyletic origin of C. niveatus. We considered species misidentification to be the main hypothesis. However, additional data is essential to test these proposed hypotheses.     

The complete mitochondrial genome of Parasesarma pictum (Brachyura: Grapsoidea: Sesarmidae) and comparison with other Brachyuran crabs

Mitochondrial DNA (mtDNA) is an extrachromosomal genome which can provide important information for evolution and phylogenetic analysis. In this study, we assembled a complete mitogenome of a crab Parasesarma pictum (Brachyura: Grapsoidea: Sesarmidae) from next generation sequencing reads at the first time. P. pictum is a mudflat crab, belonging to the Sesarmidae family (subfamily Sesarminae), which is perched on East Asia. The 15,716 bp mitogenome covers 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes (rRNAs), and one control region (CR). The control region spanns 420 bp. The genome composition was highly A+T biased 75.60% and showed negative AT-skew (−0.03) and negative GC-skew (−0.47). Compared with the ancestor of Brachyura, the gene order of Sesarmidae has several differences and the gene order of P. pictum is typical for mitogenomes of Sesarmidae. Phylogenetic tree based on nucleotide sequences of mitochondrial 13 PCGs using BI and ML determined that P. pictum has a sister group relationship with Parasesarma tripectinis and belongs to Sesarmidae.     

Pattern of genetic variation of yellow catfish Pelteobagrus fulvidraco Richardso in Huaihe river and the Yangtze river revealed using mitochondrial DNA control region sequences

Genetic variability and population genetic structure of the yellow catfish Pelteobagrus fulvidraco Richardso in the Huaihe river and the Yangtze river was examined with a 810-bp of the mitochondrial DNA control region. A total of 70 haplotypes were identified from 145 samples, which were characterized with high haplotype diversity (h = 0.9832 ± 0.0041) but low nucleotide diversity (π = 0.0415 ± 0.0201). The analysis of molecular variance and phylogenetic reconstructions detected significant geographic structure between Huaihe river and Yangtze with F_ST = 0.1183 (P = 0.0000). Neighbor-joining (NJ) phylogenetic analyses identified two distinct clades (bootstrap support 99 %). The medium joining network drawn using the complete data set was reticulated and also distinctly split the 70 haplotypes into two groups corresponding to those of the NJ tree. Departures from neutrality were not significant for the Huaihe river and the Yangtze river Pelteobagrus fulvidraco, concordant with the observed multimodal mismatch distributions (P > 0.05), which suggested that the effective size of this species has been large and stable for a long period. The question about the existence of significant genetic differentiation for Pelteobagrus fulvidraco in the Yangtze river and Huaihe river basins remains to be further studied with molecular nuclear markers and larger sample sizes from throughout the river basins.     

Mitogenome of Coprophanaeus ensifer and phylogenetic analysis of the Scarabaeidae family (Coleoptera)

Several studies about the phylogenetic relationships of the Scarabaeinae subfamily (Coleoptera: Scarabaeidae) have been performed, but some phylogenetic uncertainties persist including the relationship and monophyly of different tribes and some genera. The aim of this study was to characterize the mitogenome of Coprophanaeus ensifer in order to establish its position within the Scarabaeidae family and to contribute to the resolution of some phylogenetic uncertainties. The mitogenome was sequenced on the Illumina HiSeq 4000, assembled using the Mitobim software and annotated in MITOS WebServer. The phylogenetic trees were reconstructed by Bayesian inference. The C. ensifer mitogenome is a molecule of 14,964 bp that contains the number and organization of the genes similar to those of most Coleoptera species. Phylogenetic reconstruction suggests monophyly of the tribe Phanaeini and supports the hypothesis that Coprini is a sister group of Phanaeini. The results also revealed the position of the tribe Oniticellini which is grouped with Onthophagini and Onitini. The geographic distribution of these species that form the most ancestral clade suggests with Scarabaeinae originated in Africa. Keywords: Dung beetle, mitochondrial genome, phylogenomics     

Complete mitochondrial genome of Neochauliodes parasparsus (Megaloptera: Corydalidae) with phylogenetic consideration

We sequenced the complete mitochondrial genome (mitogenome) of Neochauliodes parasparsus. The 15,995-bp mitogenome contained the standard set of 13 protein-coding genes, 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes (rRNAs), and a putative control region, with a gene arrangement that was identical to that reported for most other megalopteran species. We also predicted the secondary structure of all the RNA genes and analysed the preferred codon usage of the protein-coding genes. The putative 1265-bp control region contained two tandem repeated regions and several microsatellite-like elements. The phylogenetic analysis of available neuropteridan mitogenomes, based on the 13 protein-coding genes, appeared to support the current view of the neuropteridan phylogeny, and among the Neochauliodes spp., N. parasparsus was the most closely related to N. punctatolosus.     

The mitogenomes of three beetles (Coleoptera: Polyphaga: Cucujiformia): New gene rearrangement and phylogeny

The mitochondrial genome (mitogenome) has been extensively used for studying phylogenetic relationships at different taxonomic levels. Several molecular analyses have been performed, but the phylogenetic relationships among infraorders in Polyphaga have not been well resolved. In this work, three nearly complete mitogenomes of Coleoptera, Sitophilus oryzae, Oryzaephilus surinamensis and Callosobruchus chinensis, were determined. The O. surinamensis and S. oryzae mitogenomes harbor gene content typical of other Polyphaga mitogenomes, while a gene rearrangement (trnQ) was found in the C. chinensis mitogenome. The mitogenomes of these three Coleoptera species each consist of approximately 13 protein-coding genes, 22 tRNA genes, two rRNA genes and one A + T-rich region. Phylogenetic analysis within Polyphaga was carried out based on mitochondrial data. The phylogenetic results within Polyphaga support the basal position of Cyphon sp., which belonged to Scirtoidea, Elateriformia. Within Cucujiformia, monophyletic Curculionoidea, Chrysomeloidea and Tenebrionoidea were confirmed.     

The complete mitochondrial genome of cricket Sclerogryllus punctatus (Orthoptera: Gryllidae) and phylogenetic analysis

The crickets of genus Sclerogryllus Gorochov, 1985 belongs to subfamily Sclerogryllinae of family Gryllidae. In this study, we report the first complete mitogenome sequences of the genus Sclerogryllus, and analyze the features of mitogenomes of S. punctatus. The mitogenome of S. punctatus was 15,438 bp and consisted of 37 genes, coding for 13 proteins, 2 ribosomal RNA (rRNA) and 22 transfer RNA (tRNA), and a control region. S. punctatus shares the arrangement of trnE-trnS-trnN with most mitogenomes of Grylloidea. Besides, the tRNAs possess the typical cloverleaf secondary structure except for the trnS1 (AGN) gene. The phylogenetic analysis using 13 protein-coding genes and 2 rRNA represents that genus Sclerogryllus is included in subfamily Gryllinae. Our results uncover the phylogenetic position of genus Sclerogryllus by mitogenome data within the family Gryllidae.     

Complete mitochondrial genome of Periplaneta brunnea (Blattodea: Blattidae) and phylogenetic analyses within Blattodea

The complete mitochondrial genome (mitogenome) of Periplaneta brunnea was sequenced in this study and used to reconstruct the phylogenetic relationship of Blattodea. The circular mitogenome was 15,604?bp long and exhibited typical gene organization and order, consistent with other sequenced Periplaneta mitogenomes. The initiation codon of the P. brunnea COX1 gene was unusual in that no typical ATN or TTG start codon was found. The two longest intergenic spacer sequences found in the P. brunnea mitogenome were 21 and 17?bp long. Twenty-one base spacer had a 4?bp motif (TATT) between tRNA-Glu and tRNA-Met that conservatively displayed in 9 sequenced blattarian mitogenomes. The second spacer was between tRNA-Ser (UCN) and NAD1 containing a 7?bp motif (WACTTAA) that was highly conserved in 14 blattarian mitogenomes. The control region showed a relatively fixed motif present in 6 Blattidae mitogenomes, with a big stem-loop structure. Phylogenetic analyses were conducted using site-homogeneous models based on 13 protein-coding genes (PCGs) and two RNA genes. The trees derived from Bayesian inference and maximum likelihood analyses and recovered a relatively stable relationship among major lineages except for the position of Polyphagidae and inter-family relationships of Blaberidae. Analyses supported the monophyly of Blattidae, Blaberidae, Blattellidae, Polyphagidae, Dictyoptera, and the paraphyly of Blattaria. We also found Mantodea was the sister clade to (Blattaria?+?Isoptera), being the basal position of Dictyoptera in all topologies. Meanwhile, our results also consistently supported that Isoptera should be clustered with Blattaria of Blattodea.     

Novel gene rearrangement in the mitochondrial genome of Coenobita brevimanus (Anomura: Coenobitidae) and phylogenetic implications for Anomura

The complete mitochondrial genomes (mitogenomes) can indicate phylogenetic relationships among organisms, as well as useful information about the process of molecular evolution and gene rearrangement mechanisms. However, knowledge on the complete mitogenome of Coenobitidae (Decapoda: Anomura) is quite scarce. Here, we describe in detail the complete mitogenome of Coenobita brevimanus, which is 16,393 bp in length, and contains 13 protein-coding genes, two ribosomal RNA, 22 transfer RNA genes, as well as a putative control region. The genome composition shows a moderate A + T bias (65.0%), and exhibited a negative AT-skew (−0.148) and a positive GC-skew (0.183). Five gene clusters (or genes) involving eleven tRNAs and two PCGs were found to have rearranged with respect to the pancrustacean ground pattern gene order. Duplication-random loss and recombination models were determined as most likely to explain the observed large-scale gene rearrangements. Phylogenetic analysis placed all Coenobitidae species into one clade. The polyphyly of Paguroidea was well supported, whereas the non-monophyly of Galatheoidea was inconsistence with previous findings on Anomura. Taken together, our results help to better understand gene rearrangement process and the evolutionary status of C. brevimanus and lay a foundation for further phylogenetic studies of Anomura.     

Characterization of the complete mitochondrial genome of Drawida gisti (Metagynophora,Moniligastridae) and comparison with other Metagynophora species

Here, the complete mitochondrial genome (mitogenome) of Drawida gisti was sequenced and compared with the mitogenomes of other Metagynophora species. The circular mitogenome was 14,648 bp in length and contained two ribosomal RNA genes (rRNAs), 13 protein-coding genes (PCGs), and 22 transfer RNA genes (tRNAs). The types of constitutive genes and the direction of the coding strand that appeared in Drawida mitogenome were identical to those observed in other Metagynophora species, except for a missing lengthy non-coding region. The conservative relationships between Drawida species were supported by the overall analyses of 13 PCGs, two rRNAs, and 22 tRNAs. A comparison of the Metagynophora mitogenomes revealed that the ATP8 gene possessed the highest polymorphism among the 13 PCGs and two rRNAs. Phylogenetic analysis suggested that the Moniligastridae contained Drawida, which is a primitive Metagynophora group. Our study provides a step forward toward elucidating the evolutionary linkages within Drawida and even Metagynophora.     

The complete mitochondrial genome sequence of the little egret (Egretta garzetta)

Many phylogenetic questions in the Ciconiiformes remain unresolved and complete mitogenome data are urgently needed for further molecular investigation. In this work, we determined the complete mitogenome sequence of the little egret (Egretta garzetta). The genome was 17,361 bp in length and the gene organization was typical of other avian mtDNA. In protein-coding genes (PCGs), a C insertion was found in ND3, and COIII and ND4 terminated with incomplete stop codons (T). tRNA-Val and tRNA-Ser (AGY) were unable to fold into canonical cloverleaf secondary structures because they had lost the DHU arms. Long repetitive sequences consisting of five types of tandem repeats were found at the 3′ end of Domain III in the control region. A phylogenetic analysis of 11 species of Ciconiiformes was done using complete mitogenome data and 12 PCGs. The tree topologies obtained with these two strategies were identical, which strongly confirmed the monophyly of Ardeidae, Threskiorothidae and Ciconiidae. The phylogenetic analysis also revealed that Egretta was more closely related to Ardea than to Nycticorax in the Ardeidae, and Platalea was more closely related to Threskiornis than to Nipponia in the Threskiornithidae. These findings contribute to our understanding of the phylogenetic relationships of Ciconiiformes based on complete mitogenome data.     

The First Mitochondrial Genome for the Superfamily Hagloidea and Implications for Its Systematic Status in Ensifera

Hagloidea Handlirsch, 1906 was an ancient group of Ensifera, that was much more diverse in the past extending at least into the Triassic, apparently diminishing in diversity through the Cretaceous, and now only represented by a few extant species. In this paper, we report the complete mitochondrial genome (mitogenome) of Tarragoilus diuturnus Gorochov, 2001, representing the first mitogenome of the superfamily Hagloidea. The size of the entire mitogenome of T. diuturnus is 16144 bp, containing 13 protein-coding genes (PCGs), 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes and one control region. The order and orientation of the gene arrangement pattern is identical to that of D. yakuba and most ensiferans species. A phylogenomic analysis was carried out based on the concatenated dataset of 13 PCGs and 2 rRNA genes from mitogenome sequences of 15 ensiferan species, comprising four superfamilies Grylloidea, Tettigonioidae, Rhaphidophoroidea and Hagloidea. Both maximum likelihood and Bayesian inference analyses strongly support Hagloidea T. diuturnus and Rhaphidophoroidea Troglophilus neglectus as forming a monophyletic group, sister to the Tettigonioidea. The relationships among four superfamilies of Ensifera were (Grylloidea, (Tettigonioidea, (Hagloidea, Rhaphidophoroidea))).     

Characterization of the complete mitogenome of Trachylophus sinensis (Coleoptera: Cerambycidae: Cerambycinae), the type species of Trachylophus and its phylogenetic implications

Complete mitochondrial genomes (mitogenomes) have long been proved as reliable markers for phylogenetic reconstruction among diverse animal groups, especially benefited from recent rapid development of sequencing techniques. However, the mitogenomes of many important clades remain poorly represented, which restricted the understanding of macroscale evolutionary history of these groups. Here, we sequenced and characterized the complete mitogenome of Trachylophus sinensis, a type species of the Trachylophus genus, which also represents the first sequenced mitogenome in this genus. The complete circular mitogenome was 15,746 bp in length, containing 37 typical genes and one noncoding AT-rich control region. The nucleotide composition of the mitogenome was highly A + T biased, accounting for 70.07 % of the whole mitogenome with a slightly positive AT skewness (0.106). The 13 Protein coding genes (PCGs) used ATN as their start codons, except nad1 which used TTG. All tRNA genes were predicted with a characteristic cloverleaf secondary structure except trnS1^(AGN), whose dihydrouridine (DHU) arm was replaced by a simple loop. Phylogenetic analyses recovered Cerambycinae as a monophyletic group with high node supports and the sister relationship between T. sinensis and Nadezhdiella cantori. However, we found that deeper nodes showed not strong support, which may be caused by limited taxa sampling in our study. More mitogenomes should be sequenced representing various taxonomic levels, especially closely related species, which will enhance our understanding of phylogenetic relationships among Cerambycinae.