ATP6 Gene Research Articles

A Mutation in Mouse MT-ATP6 Gene Induces Respiration Defects and Opposed Effects on the Cell Tumorigenic Phenotype.

As the last step of the OXPHOS system, mitochondrial ATP synthase (or complex V) is responsible for ATP production by using the generated proton gradient, but also has an impact on other important functions linked to this system. Mutations either in complex V structural subunits, especially in mtDNA-encoded ATP6 gene, or in its assembly factors, are the molecular cause of a wide variety of human diseases, most of them classified as neurodegenerative disorders. The role of ATP synthase alterations in cancer development or metastasis has also been postulated. In this work, we reported the generation and characterization of the first mt-Atp6 pathological mutation in mouse cells, an m.8414A>G transition that promotes an amino acid change from Asn to Ser at a highly conserved residue of the protein (p.N163S), located near the path followed by protons from the intermembrane space to the mitochondrial matrix. The phenotypic consequences of the p.N163S change reproduce the effects of MT-ATP6 mutations in human diseases, such as dependence on glycolysis, defective OXPHOS activity, ATP synthesis impairment, increased ROS generation or mitochondrial membrane potential alteration. These observations demonstrate that this mutant cell line could be of great interest for the generation of mouse models with the aim of studying human diseases caused by alterations in ATP synthase. On the other hand, mutant cells showed lower migration capacity, higher expression of MHC-I and slightly lower levels of HIF-1α, indicating a possible reduction of their tumorigenic potential. These results could suggest a protective role of ATP synthase inhibition against tumor transformation that could open the door to new therapeutic strategies in those cancer types relying on OXPHOS metabolism.

Comparative mitochondrial genomics and phylogenetics for species of the snakehead genus Channa Scopoli, 1777 (Perciformes: Channidae)

The family Channidae, members of which are commonly known as snakehead fish, includes 53 Channa species and three Parachanna species. In this study, we characterized mitochondrial genomes (mitogenomes) of five Channa species (C. andrao, C. bleheri, C. ornatipinnis, C. pulchra, and C. stewartii) for the first time. We compared the mitogenomes with the mitogenomes of 11 other Channidae fish. The newly sequenced mitogenomes were 16,714 – 16,895 bp in length and contained 37 typical genes [13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs) and 22 transfer RNA genes (tRNAs)]. Positive AT-skews and negative GC-skews were found in the mitogenomes of Channidae. Most PCGs started with the conventional start codon, ATN; however, the sequence of the stop codon was variable. There was no essential difference in relative synonymous codon usage (RSCU) among the Channidae mitogenomes. The fastest-evolving gene atp8 and slowest-evolving gene cox1 were identified using Ka/Ks and pairwise relative genetic distance (p-distance). The displacement loop (D-loop) regions showed great variability, which affected the size of Channa mitogenomes. One origin of replication on the light strand (OL) region was found between trnN and trnC in the mitogenomes of Channidae. Phylogenetic analysis revealed three new sister pairs (C. andrao + C. bleheri, C. ornatipinnis + C. pulchra, and C. stewartii + C. gachua). Phylogenetic relationships established between the five Channa species based on mitogenomes were also supported by their morphological characteristics and geographical distribution. The novel information we obtained about these mitogenomes will contribute to elucidating the complex relationships among Channa species.

Molecular and morphological studies on some gasteroid (Basidiomycota) fungi from Western India

The gasteroid fungi are a group of fungi in Basidiomycota that include stinkhorns, earth balls, puffballs, pseudo truffles, earth stars, and bird’s nests. In the present study, six species of gasteroid fungi belonging to four genera were collected from different forest regions in Gujarat state. Identification was carried out based on the morphological features, and molecular phylogenetic analysis using nuclear rDNA Internal Transcribed Spacer (ITS), rDNA LSU and mitochondrial ATP6 gene sequences were used for molecular identification. DNA sequencing data of different gene loci (ITS, LSU, and ATP6) were submitted into the BOLD data system for DNA barcoding. Additionally, this study provides a checklist of available molecular identification data for reported gasteroid fungi from Gujarat state.

Development of mitochondrial simple sequence repeat markers to simultaneously distinguish cytoplasmic male sterile sources in cotton.

Deleterious effects on anther development andmain economy traits caused by sterile genes or cytoplasms are one of the important genetic characteristics of cytoplasmic male sterility (CMS) systems in cotton, which severely hinder the large-scale application of "three-line" hybrids in production. Therefore, distinct characterization of each cytoplasmic type is mandatory to improve the breeding efficiency of cotton hybrids. In this study, four isonuclear-alloplasmic cotton male sterile lines withG. hirsutum (CMS-(AD)1), G. barbadense (CMS-(AD)2), G. harknessii (CMS-D2), and G. trilobum (CMS-D8) cytoplasms were first created by multiple backcrosses with common genotype Shikang126. Then, 64 pairs of mitochondrial simple sequence repeat (mtSSR) markers were designed to explore the mitochondrial DNA diversities among four isonuclear-alloplasmic cotton male sterile lines, and a total of nine pairs of polymorphic mtSSR molecular markers were successfully developed. Polymorphism analysis indicated that mtSSR59 marker correlated to the atp1 gene could effectively divide the CMS-D2, CMS-(AD)1, and CMS-(AD)2 in one category while the CMS-D8 in another category. Further cytological observation and determination of ATP contents also confirmed the accurate classification of CMS-D2 and CMS-D8 lines. Moreover, the mtSSR59 marker was successfully applied in the marker-assisted selection (MAS) for breeding new male sterile lines and precise differentiation or purity identification of different CMS-based "three-line" and conventional cotton hybrids. This study provides new technical measures for classifying various cytoplasmic sterile lines, and our results will significantly improve the efficiency of there-line hybrid breeding in cotton.

Phylogeny and population structure of Echinococcus granulosus (sensu stricto) based on full-length cytb-nad2-atp6 mitochondrial genes – First report from Sialkot District of Pakistan

Cystic echinococcosis is a zoonotic disease of livestock having serious economic setbacks. The etiological agents of the disease belong to Echinococcus granulosus sensu lato. Despite of worldwide distribution of the disease, the molecular studies mainly employ amplification of cox1, nad1 and nad5 genes. To further strengthen the knowledge about significance of other molecular markers and to investigate the genetic diversity and population structure of Echinococcus species in Pakistan, the current study was designed in which full length mitochondrial cytb, atp6 and nad2 genes were amplified. Based on BLAST searches of the generated cytb, atp6 and nad2 gene sequences from a total of 18 hydatid cysts collected from cattle, 12 isolates were identified as E. granulousus G3 and 6 as E. granulosus (G1). The phylogeny inferred by the Bayesian method using nucleotide sequences of cytb-atp6-nad2 further confirmed their identity. The diversity indices indicated a high haplotype and a low nucleotide diversity. The negative values of Tajima’s D and Fu’s Fs test demonstrated deviation from neutrality suggesting a recent population expansion. To the best of our knowledge, the present study described the genetic variation of E. granulosus population for the first time in Pakistan using full-length cytb, atp6 and nad2 mitochondrial genes. The findings on the genetic variation of E. granulosus in Pakistan will constitute useful baseline information for future studies on the prevalence and population structure of E. granulosus based on full-length cytb, atp6 and nad2.

Spatio-Temporal Evolutionary Patterns of the Pieridae Butterflies (Lepidoptera: Papilionoidea) Inferred from Mitogenomic Data.

Pieridae is one of the largest and almost cosmopolitan groups of butterflies, which plays an important role in natural ecosystems; however, to date, its phylogeny and evolutionary history have not been fully resolved. In this study, we obtained the complete or nearly complete mitochondrial genomes of 100 pierid taxa (six newly sequenced, sixty extracted from the whole-genome data, and thirty-four directly available from GenBank). At the same time, for the first time, we conducted comparative mitogenomic and phylogenetic analyses based on these mitogenomic data, to further clarify their spatio-temporal evolutionary patterns. Comparative mitogenomic analysis showed that, except for cox2, the GC content of each of the 13 protein-coding genes (PCGs) in the rapidly diverging subfamily Pierinae was higher than in its sister group Coliadinae. Moreover, the dN/dS values of nine genes (atp6, atp8, cox1, cox3, cob, nad1, nad3, nad5, and nad6) in Pierinae were also relatively higher than those in its sister group, Coliadinae. Phylogenetic analysis showed that all the resultant phylogenetic trees were generally in agreement with those of previous studies. The Pierinae family contained six clades in total with the relationship of (Leptosiaini + (((Nepheroniini + Arthocharidini) + Teracolini) + (Pierini + Elodini))). The Pieridae originated in the Palearctic region approximately 72.3 million years ago in the late Cretaceous, and the subfamily Pierinae diverged from this family around 57.9 million years ago in the Oriental region, shortly after the K-Pg mass extinction event; in addition, the spatio-temporal evolutionary patterns of Pierinae were closely correlated with geological events and environmental changes, as well as the host plant coevolutionary scenario in Earth's history. However, some incongruencies were observed between our results and those of previous studies in terms of shallow phylogenies for a few taxa, and should be further investigated.

Genetic diversity of Echinococcus granulosus sensu lato from animals and humans in Bosnia and Herzegovina

Cystic echinococcosis (CE) is recognized as one of the most prevalent zoonotic diseases in Bosnia and Herzegovina. However, no systemic investigation of the genetic diversity of Echinococcus granulosus sensu lato circulating among animals and humans in the country has been performed to date. In this preliminary study, we analysed one cyst each from 36 sheep, 27 cattle, 27 pigs, 11 wild boars and 16 human patients for amplification and partial sequencing of the adenosine triphosphate 6 (atp6) and cytochrome c oxidase 1 (cox1) genes. The host species, fertility rate and organ cyst location were recorded for each subject involved in the study. Overall, the atp6 gene was successfully amplified and sequenced from 110 samples, while 96 of the PCRs for cox1 were positive. Three zoonotic genotypes of E. granulosus sensu stricto (G1 and G3) and Echinococcus canadensis (G7) were identified in our isolates based on analyses of the atp6 gene. These genotypes were represented by 11 different genetic variants (haplotypes), six of which were identified for the first time in the present study. This study demonstrates, for the first time, that CE in Bosnia and Herzegovina is predominantly caused by E. granulosus sensu stricto and E. canadensis clusters, which exhibited a lower genetic diversity compared to isolates from other European countries. Further molecular studies employing other mitochondrial and nuclear genes are required to better understand the transmission cycles of E. granulosus sensu stricto among intermediate and definitive hosts in the country.

Characterization and phylogenetic implications of newly sequenced mitogenomes of Five Mileewa and Processina species from China (Hemiptera: Cicadellidae: Mileewinae)

To accumulate evidence of the phylogeny of Mileewinae and the relationships among Mileewa, Processina, and Ujna genera, we sequenced the complete mitochondrial genomes of four Mileewa spp., namely, Mileewa mira, Mileewa lamellata, Mileewa sharpa, and Mileewa amplimacula. The first complete mitogenome of the genus Processina (P. sexmaculata), established by Yang, Deitz & Li from China and comprising five species, was also sequenced in this study. Annotation showed that the five mitogenomes were 14787 –15436 bp in length, and all harbored 37 typical genes. The AT content of the five mitogenomes ranged from 78.3% to 80.2%, which was similar to that of other sequenced Mileewinae species. For protein-coding genes (PCGs), ATN was the start codon, while atp8 and nad5 genes were initiated with TTG, and a great majority of them used TAA or TAG as stop codons, whereas cox2 and nad1 ended with an incomplete codon T–. All tRNAs had a typical cloverleaf secondary structure, except for trnS1, which had a reduced dihydrouridine arm. We further used 59 Membracoidea species and two outgroups to reconstruct phylogenetic trees based on 13 PCGs under an independent partition model with Bayesian inference and Maximum-likelihood methods. Among these two trees, each of the subfamilies Cicadellinae, Typhlocybinae, and Mileewinae were recovered as a monophyletic group with high support values, suggesting that Typhlocybinae was more ancient than Mileewinae and Cicadellinae. Within the Mileewinae subfamily, all species maintained the same relationships and topologies according to both the BI and ML analyses (PP > 0.8, BS > 83) as follows: (M. sharpa + (U. puerana + ((M. ponta + (M. mira + M. lamellata)) + ((M. albovittata + (M. margheritae + M. amplimacula)) + (M. rufivena + (P. sexmaculata + M. alara)))))), and the monophyly of the genera Processina, Mileewa and Ujna were not supported. This study further enriches the Mileewinae mitogenome database and will contribute to future research on the systematics, evolution, and classification of this group.

The complete mitochondrial genome of Tuta absoluta (Lepidoptera: Gelechiidae) and genetic variation in two newly invaded populations in China

• The size of mitogenome sequences in T. absoluta varied among individuals from different geographical locations. • The differences in the lengths of intergenic spacer were contributed to the size difference of mitogenomes among different populations. • cox2 , atp6 , nad1 and nad5 genes were sensitive mitochondrial gene markers for population genetics in T. absoluta . Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a devastating invasive pest worldwide, causing severe damage to tomatoes. Recently, it has been recorded in the northwestern and southwestern parts of China. Here, the mitogenomes and genetic variation of two newly invaded T. absoluta populations in Xinjiang and Yunnan, were determined. The results showed that the complete mitogenome size of T. absoluta is 15298 bp for the individual from Xinjiang and 15296 bp for the individual from Yunnan, which were both longer than the reported mitogenome from Spain (15290 bp). The mitogenome sequences of individuals collected from three locations showed high levels of sequence similarity, except for 8 polymorphic sites, which were in genes cox2 (1 site), cox3 (2 sites), cob (1 site) , atp6 (1 site), nad1 (2 sites) and nad5 (1 site). Tuta absoluta mitogenomes share many features with other 6 Gelechiidae mitogenomes, except for several differences in the start and stop codons of protein-coding genes and the length of intergenic spacers. Seven partial mitochondrial genes ( cox1 , cox2 , cox3 , atp6 , cob , nad1 , and nad5 ) were used for genetic variation analysis, and significant population differentiation was found between the two populations based on cox2 , atp6 , nad1 , and nad5 . The complete mitogenomes and sensitive mitochondrial gene markers reported here provide useful data for further population genetics study of this pest.

Deficiency of the ATP Synthase Caused by nt 8993 Mutation and its Impact on Human Health

The ATP synthase in mitochondria was responsible for the synthesis of ATP to provide chemical energy for the cell to achieve metabolism. The point mutation at the mitochondrial DNA nt 8993(T>C and T>G) disrupted the normal cellular mechanism of the ATP synthase, causing a deficiency in the production of ATP synthesis. The mitochondrial nt 8993 mutation causes a replacement of leucine amino acid with an arginine(aL156R), changing the sequence of the mitochondrial ATP6 gene, which causes an inefficiency in the c-subunit of the ATP synthase. The potential effect of the nt 8993 mutation can be expressed in Leigh syndrome, which exhibited in neurologic weakness, ataxia, and retinitis pigmentosa. In this review, we will go over the structure of the ATP synthase, mechanism of the mitochondrial nt 8993 mutation, and potential cellular mechanisms to eliminate the mutation.

Complete mitogenome of Calliptamus barbarus Costa (Orthoptera: Acrididae) and its phylogeny in Acridoidea

Calliptamus barbarus Costa is a species in genus Calliptamus, belonging to the Calliptaminae, Acrididae, Orthoptera. In the present study, the mitogenome of C. barbarous was determined and annotated to better identify C. barbarous and other related species. The mitogenome was 15,686 bp in length and encoded 37 genes, including 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a control region. The nucleotide composition analysis of the mitogenome showed a strong bias of A/T, with A+T content of 72.7%, being similar to other reported mitogenomes. All the 13-PCGs used typical start codons of ATN and stop codons of TAA/G. All of the transfer RNA genes had typical clover-leaf structure except the missing dihydrouidine (DHU) arm of tRNASer1. Interestingly, we observed two overlapped but conserved regions between ATP8 and ATP6 genes, ND4 and ND4L genes. The results of Ka/Ks implied that CytB is more conservative than COX1. Phylogenetic analyses based on the 13-PCGs from 30 species indicated strong support for the monophyly of Acridoidea and represented the main topology as follows: (Oedipodinae+ (Acridinae+ (Gomphocerinae +((Calliptaminae+Catantopinae) +(Oxyinae+Melanoplinae))))). The phylogenetic relationship indicated that the molecular taxonomy of C. barbarous was consistent with the current morphological classification. The data in the present study will further enrich the mitogenome database of Acridoidea and provided useful clues for further research of C. barbarous on the mitogenome evolution and diversification of Calliptamus.

Variations in mitochondrial DNA coding and D-loop region are associated with early embryonic development defects in infertile women.

Mitochondrial DNA (mtDNA) plays a critical role in oocyte maturation, fertilization, and early embryonic development. Defects in mtDNA may determine the alteration of the mitochondrial function, affecting cellular oxidative phosphorylation and ATP supply, leading to impaired oocyte maturation, abnormal fertilization, and low embryonic developmental potential, ultimately leading to female infertility. This case-control study was established to investigate the correlation between mtDNA variations and early embryonic development defects. Peripheral blood was collected for next-generation sequencing from women who suffered the repeated failures of in vitro fertilization (IVF) and/or intracytoplasmic sperm injection (ICSI) cycles due to early embryonic development defects as well as in-house healthycontrols, and the sequencing results were statistically analyzed for all subjects. This study found that infertile women with early embryonic development defects carried more mtDNA variants, especially in the D-loop region, ATP6 gene, and CYTB gene. By univariate logistic regression analysis, 16 mtDNA variants were associated with an increased risk of early embryonic development defects (OR > 1, p < 0.05). Furthermore, we identified 16 potentially pathogenic mtDNA variants only in infertile cases. The data proved that mtDNA variations were associated with early embryonic development defects in infertile Chinese women.

Complete mitogenome and phylogenetic analysis of the tropical rocky shore crab Grapsus albolineatus (Lamarck, 1818) (Crustacea: Grapsoidea)

In this study, the complete mitogenome of Grapsus albolineatus (Lamarck, 1818) (Crustacea: Grapsoidea) was sequenced. The mitogenome of G. albolineatus was a circular molecule with 15,578 bp length. Its nucleotide composition was 26.81% A, 16.37% G, 34.51% T, and 22.31% C. It comprised 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA), and two ribosomal RNA (rRNA). All PCGs were initiated by ATN codons, except for the atp8 and nad1 genes. Ten PCGs used a common stop codon of TAA or TAG, and the other three ended with a truncated stop codon (a single stop nucleotide T). Phylogenetic analysis revealed that G. albolineatus was closely related to species from the genera Pachygrapsus and Metopograpsus.

Complete mitochondrial genome of the branching octocoral Paramuricea grayi (Johnson, 1861), phylogenetic relationships and divergence analysis

The Gray’s sea fan, Paramuricea grayi (Johnson, 1861), typically inhabits deep littoral and circalittoral habitats of the eastern temperate and tropical Atlantic Ocean. Along the Iberian Peninsula, where P. grayi is a dominant constituent of circalittoral coral gardens, two segregating lineages (yellow and purple morphotypes) were recently identified using single-copy nuclear orthologues. The mitochondrial genomes of 9 P. grayi individuals covering both color morphotypes were assembled from RNA-seq data, using samples collected at three sites in southern (Sagres and Tavira) and western (Cape Espichel) Portugal. The complete circular mitogenome is 18,668 bp in length, has an A + T-rich base composition (62.5%) and contains the 17 genes typically found in Octocorallia: 14 protein-coding genes (atp6, atp8, cob, cox1-3, mt-mutS, nad1-6, and nad4L), the small and large subunit rRNAs (rns and rnl), and one transfer RNA (trnM). The mitogenomes were nearly identical for all specimens, though we identified a noteworthy polymorphism (two SNPs 9 bp apart) in the mt-mutS of one purple individual that is shared with the sister species P. clavata. The mitogenomes of the two species have a pairwise sequence identity of 99.0%, with nad6 and mt-mutS having the highest rates of non-synonymous substitutions.

Mitochondrial genomic analyses provide new insights into the “missing” atp8 and adaptive evolution of Mytilidae

BackgroundMytilidae, also known as marine mussels, are widely distributed in the oceans worldwide. Members of Mytilidae show a tremendous range of ecological adaptions, from the species distributed in freshwater to those that inhabit in deep-sea. Mitochondria play an important role in energy metabolism, which might contribute to the adaptation of Mytilidae to different environments. In addition, some bivalve species are thought to lack the mitochondrial protein-coding gene ATP synthase F0 subunit 8. Increasing studies indicated that the absence of atp8 may be caused by annotation difficulties for atp8 gene is characterized by highly divergent, variable length.ResultsIn this study, the complete mitochondrial genomes of three marine mussels (Xenostrobus securis, Bathymodiolus puteoserpentis, Gigantidas vrijenhoeki) were newly assembled, with the lengths of 14,972 bp, 20,482, and 17,786 bp, respectively. We annotated atp8 in the sequences that we assembled and the sequences lacking atp8. The newly annotated atp8 sequences all have one predicted transmembrane domain, a similar hydropathy profile, as well as the C-terminal region with positively charged amino acids. Furthermore, we reconstructed the phylogenetic trees and performed positive selection analysis. The results showed that the deep-sea bathymodiolines experienced more relaxed evolutionary constraints. And signatures of positive selection were detected in nad4 of Limnoperna fortunei, which may contribute to the survival and/or thriving of this species in freshwater.ConclusionsOur analysis supported that atp8 may not be missing in the Mytilidae. And our results provided evidence that the mitochondrial genes may contribute to the adaptation of Mytilidae to different environments.

The complete mitochondrial genome of Saccostrea malabonensis (Ostreida: Ostreidae): characterization and phylogenetic position

The taxonomy of the genus Saccostrea is very confused, however, there is relatively little molecular information available on Saccostrea. In this study, we determined and described for the first time the complete mitochondrial genome of Saccostrea malabonensis. The complete mitogenome of S. malabonensis is 16,204 bp in length, containing 12 protein-coding genes (lack of atp8 gene), two rRNA genes, 23 tRNA genes. The overall nucleotide composition of S. malabonensis has an AT content of 61.94% (26.29% A, 15.71% C, 22.35% G, 35.65% T). Phylogenetic analyses showed that S. malabonensis is first clustered with S. cucullata then united with Saccostrea kegaki.

Phylogenomics, plastome degradation and mycoheterotrophy evolution of Neottieae (Orchidaceae), with emphasis on the systematic position and Loess Plateau-Changbai Mountains disjunction of Diplandrorchis

BackgroundMycoheterotrophy is a unique survival strategy adapted to dense forests and has attracted biologists’ attention for centuries. However, its evolutionary origin and related plastome degradation are poorly understood. The tribe Neottieae contains various nutrition types, i.e., autotrophy, mixotrophy, and mycoheterotrophy. Here, we present a comprehensive phylogenetic analysis of the tribe based on plastome and nuclear ITS data. We inferred the evolutionary shift of nutrition types, constructed the patterns of plastome degradation, and estimated divergence times and ancestral ranges. We also used an integration of molecular dating and ecological niche modeling methods to investigate the disjunction between the Loess Plateau and Changbai Mountains in Diplandrorchis, a mycoheterotrophic genus endemic to China that was included in a molecular phylogenetic study for the first time.ResultsDiplandrorchis was imbedded within Neottia and formed a clade with four mycoheterotrophic species. Autotrophy is the ancestral state in Neottieae, mixotrophy independently originated at least five times, and three shifts from mixotrophy to mycoheterotrophy independently occurred. The five mixotrophic lineages possess all plastid genes or lost partial/all ndh genes, whereas each of the three mycoheterotroph lineages has a highly reduced plastome: one lost part of its ndh genes and a few photosynthesis-related genes, and the other two lost almost all ndh, photosynthesis-related, rpo, and atp genes. These three mycoheterotrophic lineages originated at about 26.40 Ma, 25.84 Ma, and 9.22 Ma, respectively. Diplandrorchis had presumably a wide range in the Pliocene and migrated southward in the Pleistocene.ConclusionsThe Pleistocene climatic fluctuations and the resultant migration resulted in the Loess Plateau-Changbai Mountains disjunction of Diplandrorchis. In the evolution of mycoheterotrophic lineages, the loss of plastid-encoded genes and plastome degradation are staged and irreversible, constraining mycoheterotrophs to inhabit understories with low light levels. Accordingly, the rise of local forests might have promoted the origin of conditions in which mycoheterotrophy is advantageous.

Characterization, Comparison of Two New Mitogenomes of Crocodile Newts Tylototriton (Caudata: Salamandridae), and Phylogenetic Implications.

Mitochondrial genomes (mitogenomes) are valuable resources in molecular and evolutionary studies, such as phylogeny and population genetics. The complete mitogenomes of two crocodile newts, Tylototriton broadoridgus and Tylototriton gaowangjienensis, were sequenced, assembled, and annotated for the first time using next-generation sequencing. The complete mitogenomes of T. broadoridgus and T. gaowangjienensis were 16,265 bp and 16,259 bp in lengths, which both composed of 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes, and 1 control region. The two mitogenomes had high A + T content with positive AT-skew and negative GC-skew patterns. The ratio of non-synonymous and synonymous substitutions showed that, relatively, the ATP8 gene evolved the fastest and COI evolved the slowest among the 13 PCGs. Phylogenetic trees from BI and ML analyses resulted in identical topologies, where the Tylototriton split into two groups corresponding to two subgenera. Both T. broadoridgus and T. gaowangjienensis sequenced here belonged to the subgenus Yaotriton, and these two species shared a tentative sister group relationship. The two mitogenomes reported in this study provided valuable data for future molecular and evolutionary studies of the genus Tylotoriton and other salamanders.

Allelic variability and transferability of atp6 gene among Allium species

Allelic variability and transferability of atp6 gene among Allium species

The complete mitogenome of Echinoparyphium aconiatum (Digenea: Echinostomatidae) and a comparison with other digenean species

Echinoparyphium aconiatum (Digenea: Echinostomatidae) is an intestinal parasite of anatid and snail-eating birds. In Eurasia, it is also common in lymnaeid snails, which may serve as the first and second intermediate hosts. The systematics of its genus, Echinoparyphium, have long been inadequate, with poor descriptions and extensive synonymy. To provide a basis for developing new genetic markers for studies of the identification and systematics of echinostomatids, the complete Ep. aconiatum mitogenome is described and compared with other digeneans. The circular mt molecule of this species is 14,865 bp in length, with an average A + T content of 64.33%. It contains 12 protein-coding genes and 22 transfer RNA genes. The 3′ end of nad4L overlaps the 5′ end of nad4 by 40 bp, while the atp8 gene is absent. Twenty-one transfer RNA genes transcribe products with conventional cloverleaf structures, while one transfer RNA gene has unpaired D-arms. Comparative analyses indicate that Echinoparyphium aconiatum is closely related to Echinochasmus japonicus and Echinostoma miyagawai. The phylogenetic results, using our mitochondrial data indicated Ep. aconiatum as a sister taxon of Hypoderaeum conoideum in a monophyletic clade. Our data and analyses serve as the first representative sequenced mt genome from genus Echinoparpyhium, providing additional markers to clarify the taxonomic position of Ep. aconiatum.