Complete mitochondrial genome and phylogenetic analysis of the marine microalga Symbiochlorum hainanensis (Ulvophyceae, Chlorophyta)

Symbiochlorum hainanensis Gong et al. (2018). is a unicellular green alga belonging to Ulvophyceae, Chlorophyta, and considered as an important species in coral-algae symbiont areas. In this study, we revealed firstly the mitochondrial genome sequence of the S. hainanensis. This mitochondrial genome was a circular DNA molecule of 59,508 bp, including 24 transfer RNA genes, 3 ribosomal RNA genes, and 31 protein-coding genes. The GC content of the genome was 35.4%. The phylogenetic tree suggested that S. hainandiae was a sister to the OUU clade within the class Ulvophyceae. The mitochondrial genome structure and gene content of S. hainanensis supported that S. hainanensis was a new unidentified green alga in Ulvophyceae.

The complete mitochondrial genome of Nycteribia formosana (Diptera, Nycteribiidae)

The family Hippoboscidae is an ectoparasite that primarily inhabits bats and relies on the host's blood for sustenance. This research provides the first complete mitochondrial genome of Nycteribia formosana, which shares similar characteristics with other dipteran insects. The circularized mitochondrial genome, spanning 15,107 bp, encompasses 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNA), two ribosomal RNA genes, and a control region. The nucleotide composition of A, C, G, and T is 40.4%, 10.9%, 6.7%, and 42.0%, respectively. The findings from the phylogenetic analysis suggest that the species under investigation forms a cluster with other species belonging to the family Nycteribiidae. Consequently, this study provides valuable insights for the identification of N. formosana.

Characterization of the Cambaroides wladiwostokiensis Birstein & Vinogradov, 1934 (Decapoda: Astacidea) Mitochondrial Genome Using Genome Skimming and the Phylogenetic Implications within the Astacidea Infraorder

BACKGROUND

The mitochondrial genome is a powerful tool for exploring and confirming species identity and understanding evolutionary trajectories. The genus Cambaroides, which consists of freshwater crayfish, is recognized for its evolutionary and morphological complexities. However, comprehensive genetic and mitogenomic data on species within this genus, such as C. wladiwostokiensis, remain scarce, thereby necessitating an in-depth mitogenomic exploration to decipher its evolutionary position and validate its species identity.

METHODS

The mitochondrial genome of C. wladiwostokiensis was obtained through shallow Illumina paired-end sequencing of total DNA, followed by hybrid assembly using both de novo and reference-based techniques. Comparative analysis was performed using available Cambaroides mitochondrial genomes obtained from National Center for Biotechnology Information (NCBI). Additionally, phylogenetic analyses of 23 representatives from three families within the Astacidea infraorder were employed using the PhyloSuite platform for sequence management and phylogenetic preparation, to elucidate phylogenetic relationships via Bayesian Inference (BI), based on concatenated mitochondrial fragments.

RESULTS

The resulting genome, which spans 16,391 base pairs was investigated, revealing 13 protein-coding genes, rRNAs (12S and 16S), 19 tRNAs, and a putative control region. Comparative analysis together with five other Cambaroides mitogenomes retrieved from GenBank unveiled regions that remained unread due to challenges associated with the genome skimming technique. Protein-coding genes varied in size and typically exhibited common start (ATG) and stop (TAA) codons. However, exceptions were noted in ND5 (start codon: GTG) and ND1 (stop codon: TAG). Landscape analysis was used to explore sequence variation across the five available mitochondrial genomes of Cambaroides.

CONCLUSIONS

Collectively, these findings reveal variable sites and contribute to a deeper understanding of the genetic diversity in this genus alongside the further development of species-specific primers for noninvasive monitoring techniques. The partitioned phylogenetic analysis of Astacidea revealed a paraphyletic origin of Asian cambarids, which confirms the data in recent studies based on both multilocus analyses and integrative approaches.

In Search of the Elusive North: Evolutionary History of the Arctic Fox (Vulpes lagopus) in the Palearctic from the Late Pleistocene to the Recent Inferred from Mitogenomic Data

Despite the high level of interest, the population history of arctic foxes during the Late Pleistocene and Holocene remains poorly understood. Here we aimed to fill gaps in the demographic and colonization history of the arctic fox by analyzing new ancient DNA data from fossil specimens aged from 50 to 1 thousand years from the Northern and Polar Urals, historic DNA from museum specimens from the Novaya Zemlya Archipelago and the Taymyr Peninsula and supplementing these data by previously published sequences of recent and extinct arctic foxes from other regions. This dataset was used for reconstruction of a time-calibrated phylogeny and a temporal haplotype network covering four time intervals: Late Pleistocene (ranging from 30 to 13 thousand years bp), Holocene (ranging from 4 to 1 thousand years bp), historical (approximately 150 years), and modern. Our results revealed that Late Pleistocene specimens showed no genetic similarity to either modern or historical specimens, thus supporting the earlier hypothesis on local extinction rather than habitat tracking.

Complete mitochondrial genome of golden variant of freshwater fish Labeo rajasthanicus (Cypriniformes: Cyprinidae): endemic to India

The complete mitochondrial genome of the freshwater fish species Labeo rajasthanicus was obtained, using Illumina NovaSeq 6000 with 2 × 150 bp paired-end sequencing. The mitogenome of L. rajasthanicus is 16,738 bp in length (GenBank accession no.: OQ834146), comprised of 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and a control region, i.e. D-loop. The arrangement of genes was found to be identical to other Cypriniformes fish mitogenome, available in the NCBI database. The taxonomic status of L. rajasthanicus as a valid species was debated by some researchers and it was considered a synonym of L. boggut. However, phylogenetic analysis in the present study supports the species validity of L. rajasthanicus, as it showed a distinct node well separated from L. boggut and supported by a high bootstrap value. Furtherly, the pairwise genetic divergence among studied species showed the divergence between L. rajasthanicus and L. boggut as 1.6% whereas the minimum divergence was found to be 0.13% with L. dussumieri followed by L. fimbriatus (0.58%) and L. gonius (0.63%). The complete mitogenome of L. rajasthanicus will also be useful as a baseline reference genome for the reconstruction and annotation of the mitogenome of other Labeo species.

The complete mitochondrial genome of a new species of the genus Schizothorax from Sichuan, China (Cypriniformes: Cyprinidae)

Schizothorax gulinensis sp. nov. is a new species of the genus Schizothorax from Sichuan, China (Cypriniformes: Cyprinidae). In this study, we have first reported the complete mitochondrial genome of S. gulinensis with Illumina sequencing. There were 16,587 nucleotide pairs in the mitochondrial genome (mitogenome) of S. gulinensis, including 13 protein-coding genes (PCGs), two ribosomal RNAs (rRNAs), and 22 transfer RNAs (tRNAs), as well as one non-coding control region (CR). The proportion of nucleotides in mitochondrial genome was 29.67% (A), 25.45% (T), 17.84% (G), 27.05% (C), and A + T content was 55.12%. All PCGs have the same start codon of the standard ATG, excepting for that of NADH dehydrogenase subunit 1 (nad1) which was the ATC, NADH dehydrogenase subunit 5 (nad5) which was the ATT and cytochrome c oxidase 1 (cox1) which was the ATC. Phylogenetic analysis results supported that S. gulinensis was closely related to Schizothorax grahami. The complete mitochondrial sequence of S. gulinensis will contribute to mitochondrial genome database and provide useful resources for population genetics and evolution analyses.

Complete mitochondrial genome of the endangered Prunus pedunculata (Prunoideae, Rosaceae) in China: characterization and phylogenetic analysis

Introduction

Prunus pedunculata (Prunoideae: Rosaceae), a relic shrub with strong resistance and multiple application values, is endangered in China. Extensive research had been devoted to gene expression, molecular markers, plastid genome analysis, and genetic background investigations of P. pedunculata. However, the mitochondrial genome of this species has not been systematically described, owing to the complexity of the plant mitogenome.

Methods

In the present research, the complete mitochondrial genome of P. pedunculata was assembled, annotated, and characterized. The genomic features, gene content and repetitive sequences were analyzed. The genomic variation and phylogenetic analysis have been extensively enumerated.

Results and discussion

The P. pedunculata mitogenome is a circular molecule with a total length of 405,855 bp and a GC content of 45.63%, which are the smallest size and highest GC content among the known Prunus mitochondrial genomes. The mitogenome of P. pedunculata encodes 62 genes, including 34 unique protein-coding genes (PCGs, excluding three possible pseudogenes), three ribosomal RNA genes, and 19 transfer RNA genes. The mitogenome is rich in repetitive sequences, counting 112 simple sequence repeats, 15 tandem repeats, and 50 interspersed repetitive sequences, with a total repeat length of 11,793 bp, accounting for 2.91% of the complete genome. Leucine (Leu) was a predominant amino acid in PCGs, with a frequency of 10.67%, whereas cysteine (Cys) and tryptophan (Trp) were the least adopted. The most frequently used codon was UUU (Phe), with a relative synonymous codon usage (RSCU) value of 1.12. Selective pressure was calculated based on 20 shared PCGs in the mitogenomes of the 32 species, most of which were subjected to purifying selection (Ka/Ks < 1), whereas ccmC and ccmFn underwent positive selection. A total of 262 potential RNA editing sites in 26 PCGs were identified. Furthermore, 56 chloroplast-derived fragments were ascertained in the mitogenome, ranging from 30 to 858 bp, and were mainly located across IGS (intergenic spacer) regions or rRNA genes. These findings verify the occurrence of intracellular gene transfer events from the chloroplast to the mitochondria. Furthermore, the phylogenetic relationship of P. pedunculata was supported by the mitogenome data of 30 other taxa of the Rosaceae family. Understanding the mitochondrial genome characteristics of P. pedunculata is of great importance to promote comprehension of its genetic background and this study provides a basis for the genetic breeding of Prunus.

The complete mitochondrial genome of deep-sea ophiuroid Ophioleila elegans (Echinodermata: Ophiuroidea) from the Shkolnik Guyot, a northwest Pacific seamount

Ophiuroids are a diversified benthic taxon in the deep sea. Given their various dispersal strategies, they are considered an adequate group to assess genetic connectivity, especially in the seamounts that function as islands. Ophioleila elegans A.H. Clark, 1949, in the family Ophiothamnidae, was previously reported from the Caiwei Guyot, a seamount in the northwest Pacific Ocean. Here, we described the mitochondrial genome of O. elegans collected from another seamount in the northwest Pacific. The whole mitogenome is 16,376 bp in length and encodes 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes. Phylogenetic analysis based on the mitogenome sequences showed that O. elegans was clustered with Histampica sp., the only species for which mitogenome sequence has been reported within the family Ophiothamnidae. The complete mitogenome of O. elegans first reported in the present study provides useful information for population genetics and evolutionary relationship of this taxon, especially in the northwest Pacific seamounts.

Intrageneric structural variation in organelle genomes from the genus Dystaenia (Apiaceae): genome rearrangement and mitochondrion-to-plastid DNA transfer

Introduction

During plant evolution, intracellular DNA transfer (IDT) occurs not only from organelles to the nucleus but also between organelles. To further comprehend these events, both organelle genomes and transcriptomes are needed.

Methods

In this study, we constructed organelle genomes and transcriptomes for two Dystaenia species and described their dynamic IDTs between their nuclear and mitochondrial genomes, or plastid and mitochondrial genomes (plastome and mitogenome).

Results and Discussion

We identified the putative functional transfers of the mitochondrial genes 5' rpl2, rps10, rps14, rps19, and sdh3 to the nucleus in both Dystaenia species and detected two transcripts for the rpl2 and sdh3 genes. Additional transcriptomes from the Apicaceae species also provided evidence for the transfers and duplications of these mitochondrial genes, showing lineage-specific patterns. Intrageneric variations of the IDT were found between the Dystaenia organelle genomes. Recurrent plastid-to-mitochondrion DNA transfer events were only identified in the D. takeshimana mitogenome, and a pair of mitochondrial DNAs of plastid origin (MIPTs) may generate minor alternative isoforms. We only found a mitochondrion-to-plastid DNA transfer event in the D. ibukiensis plastome. This event may be linked to inverted repeat boundary shifts in its plastome. We inferred that the insertion region involved an MIPT that had already acquired a plastid sequence in its mitogenome via IDT. We propose that the MIPT acts as a homologous region pairing between the donor and recipient sequences. Our results provide insight into the evolution of organelle genomes across the family Apiaceae.

Complete mitochondrial genome of the western painted turtle (Chrysemys picta bellii, Testudines: Emydidae) in Korea

The complete mitochondrial genome of Chrysemys picta bellii in Korea was sequenced and characterized. The mitochondrial genome consists of 37 genes (13 protein-coding genes, 22 transfer RNA genes, and 2 ribosomal RNA genes) and a noncoding region. Phylogenetic analysis based on the mitochondrial genome sequences revealed that C. p. bellii from Korea formed a cluster with C. p. bellii from China and C. picta from the USA, while showing clear separation from other turtle species within the C. picta cluster. This study presented the first complete mitochondrial genome from C. p. bellii in Korea, offering crucial information for managing invasive species and protecting the local ecosystem.

The complete mitochondrial genome of the mauve stinger jellyfish Pelagia noctiluca Forskål, 1775 (Cnidaria, Scyphozoa, Semaeostomeae) with phylogenetic analysis

This study determined the complete mitochondrial genome of the jellyfish Pelagia noctiluca (Scyphozoa, Semaeostomeae) for the first time. The genome was a linear molecule of 16,390 bp in length and 59.3% AT. It comprised of 13 typical protein-coding genes (cox1-3, nd1-6, nd4L, atp6, atp8, and cytB), two ribosomal RNAs (16S and 12S rRNA), and two tRNAs (trnM and trnW). In addition, we detected two additional open reading frames (polB and ORF314) at one end of the genome. The gene-coding structures were identical to those of other scyphozoans. Based on a molecular phylogeny constructed using 13 protein-coding genes, P. noctiluca has the closest genetic relationship with the genus Chrysaora (Semaeostomeae).

A Comparative Analysis of Selection Pressures Suffered by Mitochondrial Genomes in Two Planthopper Species with Divergent Climate Distributions

Mitochondrial DNA (mtDNA) has been widely used as a valuable tool in studies related to evolution and population genetics, under the implicit assumption of neutral evolution. However, recent studies suggest that natural selection also plays a significant role in shaping mitochondrial genome evolution, although the specific driving forces remain elusive. In this study, we aimed to investigate whether and how climate influences mitochondrial genome evolution by comparing the selection pressures acting on mitochondrial genomes between two rice planthoppers, Sogatella furcifera (Horváth) and Laodelphax striatellus (Fallén), which have different climate distributions. We employed the dN/dS method, MK test and Tajima's D tests for our analysis. Our results showed that the mitochondrial genomes of the two species appear to undergo predominantly purifying selection, consistent with the nearly neutral evolution model. However, we observed varied degrees of purifying selection among the 13 protein-coding genes. Notably, ND1, ND2, ND6, COIII, and ATP8 exhibited significantly stronger purifying selection and greater divergence between the two species compared to the other genes. Additionally, we observed relatively stronger purifying selection in the mitochondrial genomes of S. furcifera compared to L. striatellus. This difference could be attributed to varying metabolic requirements arising from distinct habitats or other factors that are unclear here. Furthermore, we speculate that mito-nuclear epistatic interactions may play a role in maintaining nonsynonymous polymorphisms, particularly for COI and COII. Overall, our results shed some light on the influence of climate on mitochondrial genome evolution.

Complete mitochondrial genome of Mastigias papua (Scyphozoa: Rhizostomeae: Mastigiidae) based on next-generation sequencing and phylogenetic analysis

We assembled the complete mitochondrial genome (mitogenome) of Mastigias papua (Scyphozoa: Rhizostomeae: Mastigiidae) by the data generated from the next-generation sequencing platform. The complete mitogenome of M. papua was 16,560 bp in length, containing 14 protein-coding genes, two transfer RNA genes, and two ribosomal RNA genes. The base compositions were A 30.65%, C 15.16%, G 16.34%, and T 37.86%, with a gene arrangement similar to the mitogenomes derived from other representatives of Scyphozoa. Based on the 13 common protein-coding genes of 16 species within Scyphozoa, we constructed the phylogenetic tree and found that M. papua has a close relationship with Cassiopea andromeda and Cassiopea xamachana. All these species belong to an order of jellyfish Rhizostomeae, which have similar morphological characteristics. This is agreement with the conclusion we got by the phylogenetic relationship analysis using molecular data. This research has practical implications for advancing understanding of the phylogenetic relationships, taxonomic classifications, and phylogeography within Scyphozoa.

Shallow Whole-Genome Sequencing of Aedes japonicus and Aedes koreicus from Italy and an Updated Picture of Their Evolution Based on Mitogenomics and Barcoding

Aedes japonicus and Aedes koreicus are two invasive mosquitoes native to East Asia that are quickly establishing in temperate regions of Europe. Both species are vectors of arboviruses, but we currently lack a clear understanding of their evolution. Here, we present new short-read, shallow genome sequencing of A. japonicus and A. koreicus individuals from northern Italy, which we used for downstream phylogenetic and barcode analyses. We explored associated microbial DNA and found high occurrences of Delftia bacteria in both samples, but neither Asaia nor Wolbachia. We then assembled complete mitogenomes and used these data to infer divergence times estimating the split of A. japonicus from A. koreicus in the Oligocene, which was more recent than that previously reported using mitochondrial markers. We recover a younger age for most other nodes within Aedini and other Culicidae. COI barcoding and phylogenetic analyses indicate that A. japonicus yaeyamensis, A. japonicus amamiensis, and the two A. koreicus sampled from Europe should be considered as separate species within a monophyletic species complex. Our studies further clarify the evolution of A. japonicus and A. koreicus, and indicate the need to obtain whole-genome data from putative species in order to disentangle their complex patterns of evolution.

The complete mitochondrial genome of a new geographical population of freshwater fish Macropodus hongkongensis (Freyhof & Herder, 2002)

Macropodus hongkongensis (Freyhof & Herder, 2002), is sparsely distributed in Hong Kong and Guangdong provinces. Recently, a new geographical population of M. hongkongensis was discovered in the Wanquan River in the Hainan province. Therefore, this study focused on sequencing the complete mitochondrial genome of the new geographical population of Macropodus hongkongensis from the Wanquan River. The circular mtDNA molecule was 16,492 bp in size, and the overall base compositions were A (30.30%), C (24.90%), T (29.80%), and G (15.00%), with a slight bias toward A + T. The complete mitogenome encoded 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes, and a control region. Phylogenetic analysis indicated that M. hongkongensis of the Hainan Wanquan River was most closely related to the M. hongkongensis of the Gongdong population. These results provide useful genetic information for species identification and phylogenetic studies of Macropodus species.

The New Mitochondrial Genome of Hemiculterella wui (Cypriniformes, Xenocyprididae): Sequence, Structure, and Phylogenetic Analyses

Hemiculterella wui is an endemic small freshwater fish, distributed in the Pearl River system and Qiantang River, China. In this study, we identified and annotated the complete mitochondrial genome sequence of H. wui. The mitochondrial genome was 16,619 bp in length and contained 13 protein coding genes (PCGs), two rRNA genes, 22 tRNA genes, and one control region. The nucleotide composition of the mitochondrial genome was 29.9% A, 25.3% T, 27.4% C, and 17.5% G, respectively. Most PCGs used the ATG start codon, except COI and ATPase 8 started with the GTG start codon. Five PCGs used the TAA termination codon and ATPase 8 ended with the TAG stop codon, and the remaining seven genes used two incomplete stop codons (T and TA). Most of the tRNA genes showed classical cloverleaf secondary structures, except that tRNASer(AGY) lacked the dihydrouracil loop. The average Ka/Ks value of the ATPase 8 gene was the highest, while the average Ka/Ks value of the COI gene was the lowest. Phylogenetic analyses showed that H. wui has a very close relationship with Pseudohemiculter dispar and H. sauvagei. This study will provide a valuable basis for further studies of taxonomy and phylogenetic analyses in H. wui and Xenocyprididae.

Characterization of Complete Mitochondrial Genome and Phylogenetic Analysis of a Nocturnal Wasps-Provespa barthelemyi (Hymenoptera: Vespidae)

Genus Provespa contains nocturnal wasps mainly found in the southeastern region of Asia. There are no complete genome resources available of this genus, which hinders the study of its phylogenetic evolution and the origin of nocturnal behavior in the Vespidae family. Through high-throughput sequencing, we obtained the mitochondrial genome of Provespa barthelemyi (Hymenoptera: Vespidae), which is 17,721 base pairs in length and contains 13 protein-coding genes (PCGs), 22 tRNAs, and two rRNAs. We identified four gene rearrangement events of P. barthelemyi that frequently occur in the Vespidae family. We used Maximum Likelihood (ML) methodologies to construct a phylogenetic tree based on the sequenced mitochondrial genome and the available data of reported species belonging to Vespinae. Our findings confirmed the monophyly of Vespinae. Our study reports the first complete mitochondrial genome of Provespa and compares its characteristics with other mitochondrial genomes in the family Vespidae. This research should shed light on the phylogenetic relationships and ecological characteristics of the Vespidae family.

The complete mitochondrial genome of Neolissochilus soroides (Duncker, 1904) (Cypriniformes: Cyprinidae)

In this paper, we first report the complete mitochondrial genome of Neolissochilus soroides. The main purpose of this study was to determine the mitochondrial genome and phylogenetic status of N. soroides. The length mitogenome was 16584 bp, containing 2 ribosomal RNA genes, 13 protein-coding genes, 22 transfer RNA genes, and 3 non-coding control regions. The genome showed a slight A + T bias (A + T = 56.47%). 12 genes (ND1, COX2, ATP6, ND4L, ND5, ND6, ND2, ATP8, ND3, ND4, Cytb, COX3) start with ATG codon, besides one gene (COX1) start with GTG codon. Six genes (ND1, COX1, ATP6, ND4L, ND5, ND6) end with a TAA codon, 3 genes (ND2, ATP8, ND3) end with a TAG codon, and four genes (COX2, ND4, Cytb, COX3) end with the TA or T codon. The phylogenetic analysis showed that N. soroides was closely related to N. hendersoni. The mitogenome could have important implications for phylogeny, population genetics, and conservation of the N. soroides.

Characterization of the complete mitochondrial genome of Acanthogyrus (Acanthosentis) bilaspurensis Chowhan, Gupta & Khera, 1987 (Eoacanthocephala: Quadrigyridae), the smallest mitochondrial genome in Acanthocephala, and its phylogenetic implications

The phylum Acanthocephala is an important group of parasites with more than 1,300 species parasitizing intestine of all major vertebrate groups. However, our present knowledge of the mitochondrial genomes of Acanthocephala remains very limited. In the present study, we sequenced and annotated the complete mitochondrial genome of Acanthogyrus (Acanthosentis) bilaspurensis (Gyracanthocephala: Quadrigyridae) for the first time based on the specimens recovered from the intestine of common carp Cyprinus carpio Linnaeus (Cyprinidae) in Pakistan. The mitochondrial genome of A. bilaspurensis is 13,360 bp in size and contains 36 genes, representing the smallest mitogenome of acanthocephalans reported so far. The mitogenome of A. bilaspurensis also has the lowest level of overall A+T contents (59.3%) in the mitogenomes of Eoacanthocephala, and the non-coding region 3 (NCR3) lies between trnS2 and trnI, which is different from all of the other acanthocephalan species. Phylogenetic analyses based on concatenating the amino acid sequences of 12 protein-coding genes using maximum likelihood (ML) and Bayesian inference (BI) methods revealed that the family Pseudoacanthocephalidae is a sister to the Arhythmacanthidae rather than the Cavisomatidae, and the families Rhadinorhynchidae and Cavisomatidae showed sister relationships.

The complete mitochondrial genome of Semiothisa cinerearia Bremer & Grey 1853 (Lepidoptera: Geometridae: Ennominae) and its phylogenetic analysis

Semiothisa cinerearia Bremer & Grey, 1853 belongs to the lepidopteran family Geometridae, subfamily Ennominae. We sequenced the complete mitochondrial genome of S. cinerearia by PCR and Sanger sequencing method. The mitochondrial genome of S. cinerearia is 15,523 bp in length and contains a typical set of 37 genes with 'MIQ' type gene arrangement and a 394 bp AT-rich regions. Except for cox1 using CGA as initiation codon, all protein-coding genes (PCGs) start with ATN codons and except for nad2 and nad4l using TAG as termination codon, all PCGs terminated with TAA codon. A phylogenetic tree including 39 genus of subfamily Ennominae was first reconstructed based on the mitochondrial genome sequences with nucleotide substitution model GTR + G + I, which showed that the genera Amraica, Jankowskia, and Ectropis are not monophyletic and S. cinerearia and Macaria notata are classified together.

New Mitogenomes of the Green Lacewing Tribe Ankylopterygini (Neuroptera: Chrysopidae: Chrysopinae) and Phylogenetic Implications of Chrysopidae

Chrysopidae (green lacewings) are a cosmopolitan and species-rich family of Neuroptera, with remarkable significance of biological control against various agricultural and forestry pests. However, the phylogenetic position of Chrysopidae in Neuroptera and the internal relationships within the family remain equivocal among previous studies based on different types of data and sampling. Here we sequenced the mitochondrial genomes (mitogenomes) of two species of the genus Ankylopteryx in the chrysopine tribe Ankylopterygini for the first time. The characteristics of these mitogenomes were analyzed in comparison with other green lacewing mitogenomes published to date. In the phylogeny herein reconstructed based on mitogenomes, Chrysopinae were recovered as the sister group to Apochrysinae + Nothochrysinae. Within the subfamily of Chrysopinae, Nothancylini were recovered as the sister group to (Leucochrysini + Belonopterygini) + (Ankylopterygini + Chrysopini). The divergence time estimation suggested an Early Cretaceous initial divergence within the extant Chrysopidae. Within Chrysopinae, the four tribes except Nothancylini diverged around mid-Cretaceous.

Evolution of the Critically Endangered Green Sawfish Pristis zijsron (Rhinopristiformes, Pristidae), Inferred from the Whole Mitochondrial Genome

The green sawfish Pristis zijsron (Bleeker, 1851), a species of sawfish in the family Pristidae (Rhinopristiformes), mainly inhabits the Indo-West Pacific region. In this study, the complete mitochondrial genome of the critically endangered green sawfish is first described. The length of the genome is 16,804 bp, with a nucleotide composition of 32.0% A, 24.8% C, 13.1% G, and 30.0% T. It contains 37 genes in the typical gene order of fish. Two start (GTG and ATG) and two stop (TAG and TAA/T-) codons are found in the thirteen protein-coding genes. The 22 tRNA genes range from 67 bp (tRNA-Ser) to 75 bp (tRNA-Leu). The ratio of nonsynonymous substitution (Ka) and synonymous substitution (Ks) indicates that the family Pristidae are suffering a purifying selection. The reconstruction of Bayesian inference and the maximum likelihood phylogenetic tree show the same topological structure, and the family Pristidae is a monophyletic group with strong posterior probability. Pristis zijsron and P. pectinata form a sister group in the terminal clade. And the divergence time of Rhinopristiformes show that P. zijsron and P. pectinata diverged as two separate species in about Paleogene 31.53 Mya. Complete mitochondrial genomes of all five sawfishes have been published and phylogenetic relationships have been analyzed. The results of our study will provide base molecular information for subsequent research (e.g., distribution, conservation, phylogenetics, etc.) on this endangered group.

Assessing the Role of Post-Translational Modifications of Mitochondrial RNA Polymerase

The mitochondrial proteome is subject to abundant post-translational modifications, including lysine acetylation and phosphorylation of serine, threonine, and tyrosine. The biological function of the majority of these protein modifications is unknown. Proteins required for the transcription and translation of mitochondrial DNA (mtDNA) are subject to modification. This suggests that reversible post-translational modifications may serve as a regulatory mechanism for mitochondrial gene transcription, akin to mechanisms controlling nuclear gene expression. We set out to determine whether acetylation or phosphorylation controls the function of mitochondrial RNA polymerase (POLRMT). Mass spectrometry was used to identify post-translational modifications on POLRMT. We analyzed three POLRMT modification sites (lysine 402, threonine 315, threonine 993) found in distinct structural regions. Amino acid point mutants that mimic the modified and unmodified forms of POLRMT were employed to measure the effect of acetylation or phosphorylation on the promoter binding ability of POLRMT in vitro. We found a slight decrease in binding affinity for the phosphomimic at threonine 315. We did not identify large changes in viability, mtDNA content, or mitochondrial transcript level upon overexpression of POLRMT modification mimics in HeLa cells. Our results suggest minimal biological impact of the POLRMT post-translational modifications studied in our system.

Complete mitochondrial genome of Trematomus newnesi (Perciformes, Nototheniidae)

The complete mitochondrial genome of Trematomus newnesi was sequenced using an Illumina platform. The 18,602 bp mitogenome contains 13 protein-coding genes, two rRNAs, and 23 tRNAs (tRNAMet is duplicated). The eight stop codons are TAA, TAG, CTT, GTA, AAT, ACT, AGG, and TTA. Two start codons ATG and GTG are present. The GC content is 44.4% and AT content is 55.6%. A phylogenetic tree was generated using 13 species from three families. The results showed that T. newnesi is closely related to Pagothenia borchgrevinki in Nototheniidae. This study provides fundamental data for further genetic evolutionary studies on T. newnesi.

The complete mitochondrial genome of a wood-decaying fungus Vanderbylia fraxinea (Polyporaceae, Polyporales)

Vanderbylia fraxinea (Bull.) D.A. Reid, 1973 is an important wood-inhabiting fungus that plays a significant role in nutrient recycling in most forest ecosystems. In this study, the complete mitochondrial genome of V. fraxinea was characterized through de novo assembly using Illumina sequencing data and genome annotation. The mitochondrial genome is a circular molecule of 115,473 bp with a GC content of 28.66%. It comprises a total of 62 genes. Among these, 36 are protein-coding genes including 21 free-standing open reading frames (ORFs), 24 transfer RNA genes, and two ribosomal RNA genes. Core gene set commonly found in fungal mitochondrial genomes is also present in this genome, such as the apocytochrome b (cob), three subunits of the cytochrome c oxidase (cox1, cox2, and cox3), seven subunits of the NADH dehydrogenase (nad1, nad2, nad3, nad4, nad4L, nad5, and nad6), and three subunits of the ATP synthase (atp6, atp8, and atp9), as well as ribosomal RNA subunits (rns and rnl) and a set of transfer RNA genes. Phylogenetic analysis of the protein-coding sequences from the mitochondrial genome revealed a close relationship between V. fraxinea and the Ganoderma species within the Polyporaceae family.