Complete Mitochondrial DNA Sequence Research Articles

The complete mitochondrial genome sequence of Schizopygopsis younghusbandi (Cypriniformes: Cyprinidae)

In this paper, we determined complete mitochondrial DNA sequence of Schizopygopsis younghusbandi. The mitogenome is 16,674 bp in length, which includes 22 tRNA genes, 2 rRNA genes, 13 protein-coding genes, and 2 non-coding regions: control region (D-loop) and origin of light-strand replication (OL). The complete mitogenome sequence of S. younghusbandi is useful to the studies on taxonomic status, molecular systematics, stock evaluation, and conservation genetics.

The complete mitochondrial genome sequence and gene organization of the mud crab (Scylla paramamosain) with phylogenetic consideration

The complete mitochondrial genome is of great importance for better understanding the genome-level characteristics and phylogenetic relationships among related species. In the present study, we determined the complete mitochondrial genome DNA sequence of the mud crab (Scylla paramamosain) by 454 deep sequencing and Sanger sequencing approaches. The complete genome DNA was 15,824bp in length and contained a typical set of 13 protein-coding genes, 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes and a putative control region (CR). Of 37 genes, twenty-three were encoded by the heavy strand (H-strand), while the other ones were encoded by light strand (L-strand). The gene order in the mitochondrial genome was largely identical to those obtained in most arthropods, although the relative position of gene tRNAHis differed from other arthropods. Among 13 protein-coding genes, three (ATPase subunit 6 (ATP6), NADH dehydrogenase subunits 1 (ND1) and ND3) started with a rare start codon ATT, whereas, one gene cytochrome c oxidase subunit I (COI) ended with the incomplete stop codon TA. All 22 tRNAs could fold into a typical clover-leaf secondary structure, with the gene sizes ranging from 63 to 73bp. The phylogenetic analysis based on 12 concatenated protein-coding genes showed that the molecular genetic relationship of 19 species of 11 genera was identical to the traditional taxonomy.

The complete mitochondrial genome sequence of Schizothorax wangchiachii (Cypriniformes: Cyprinidae)

In this study, the complete mitochondrial DNA (mtDNA) sequence of Schizothorax wangchiachii has been determined. The mitogenome is 16,593 bp in length. It consists of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and 2 non-coding regions: origin of light-strand replication (OL) and control region (D-loop). The complete mtDNA sequence of S. wangchiachii can contribute to elucidate the evolutionary mechanisms and biogeography of Schizothorax and is useful to stock evaluation and conservation genetics for S. wangchiachii.

Mitochondrial DNA sequence of the hybrid of Squaliobarbus curriculus (♀) × Ctenopharyngodon idella (♂)

In this work, we reported the complete mitochondrial DNA sequence of the hybrid of Squaliobarbus curriculus (♀) × Ctenopharyngodon idella (♂), which was obtained by artificial hybridization. The total length of the mitochondrial genome is 16,616 bp, with the base composition of 31.15% A, 25.02% T, 27.66% C, and 16.17% G. It contains 2 ribosomal RNA genes, 13 protein-coding genes, 22 transfer RNA genes, and a major non-coding control region (D-loop region). The arrangement of these genes is the same as that found in the teleosts. All the protein initiation codons are ATG, except for COX1 that begins with GTG. The complete mitogenome of the hybrid of S. curriculus (♀) × C. idella (♂) provides an important data set for the study in genetic mechanism.

Complete mitochondrial genomes reveal phylogeny relationship and evolutionary history of the family Felidae

Many mitochondrial DNA sequences are used to estimate phylogenetic relationships among animal taxa and perform molecular phylogenetic evolution analysis. With the continuous development of sequencing technology, numerous mitochondrial sequences have been released in public databases, especially complete mitochondrial DNA sequences. Using multiple sequences is better than using single sequences for phylogenetic analysis of animals because multiple sequences have sufficient information for evolutionary process reconstruction. Therefore, we performed phylogenetic analyses of 14 species of Felidae based on complete mitochondrial genome sequences, with Canis familiaris as an outgroup, using neighbor joining, maximum likelihood, maximum parsimony, and Bayesian inference methods. The consensus phylogenetic trees supported the monophyly of Felidae, and the family could be divided into 2 subfamilies, Felinae and Pantherinae. The genus Panthera and species tigris were also studied in detail. Meanwhile, the divergence of this family was estimated by phylogenetic analysis using the Bayesian method with a relaxed molecular clock, and the results shown were consistent with previous studies. In summary, the evolution of Felidae was reconstructed by phylogenetic analysis based on mitochondrial genome sequences. The described method may be broadly applicable for phylogenetic analyses of anima taxa.

Microsatellite loci and the complete mitochondrial DNA sequence characterized through next generation sequencing and de novo genome assembly for the critically endangered orange-bellied parrot, Neophema chrysogaster

A suite of polymorphic microsatellite markers and the complete mitochondrial genome sequence was developed by next generation sequencing (NGS) for the critically endangered orange-bellied parrot, Neophema chrysogaster. A total of 14 polymorphic loci were identified and characterized using DNA extractions representing 40 individuals from Melaleuca, Tasmania, sampled in 2002. We observed moderate genetic variation across most loci (mean number of alleles per locus = 2.79; mean expected heterozygosity = 0.53) with no evidence of individual loci deviating significantly from Hardy-Weinberg equilibrium. Marker independence was confirmed with tests for linkage disequilibrium, and analyses indicated no evidence of null alleles across loci. De novo and reference-based genome assemblies performed using MIRA were used to assemble the N. chrysogaster mitochondrial genome sequence with mean coverage of 116-fold (range 89 to 142-fold). The mitochondrial genome consists of 18,034 base pairs, and a typical metazoan mitochondrial gene content consisting of 13 protein-coding genes, 2 ribosomal subunit genes, 22 transfer RNAs, and a single large non-coding region (control region). The arrangement of mitochondrial genes is also typical of Avian taxa. The annotation of the mitochondrial genome and the characterization of 14 microsatellite markers provide a valuable resource for future genetic monitoring of wild and captive N. chrysogaster populations. As found previously, NGS provides a rapid, low cost and reliable method for polymorphic nuclear genetic marker development and determining complete mitochondrial genome sequences when only a fraction of a genome is sequenced.

The complete mitochondrial genome sequence of Coilia ectenes (Clupeiformes: Engraulidae)

In this paper, the complete mitochondrial DNA (mtDNA) sequence of Coilia ectenes was determined. The complete mtDNA genome sequence of C. ectenes is 16,852 bp in length. It consists of 13 protein-coding genes, 22 transfer RNA genes, two rRNA genes and two non-coding regions. Overall base composition of mitogenome is estimated to be 31.15% for A, 27.18% for C, 15.58% for G and 26.10% for T, respectively, with a high A+T content (57.25%). The complete mitogenome of the C. ectenes can provide a basic data for the studies on population history, molecular systematics, phylogeography, stock evaluation and conservation genetics. It is also helpful to the reasonable utilization and development of rational management strategies for C. ectenes resource.

The Complete Mitochondrial Genome ofDugesia japonica(Platyhelminthes; Order Tricladida)

We used two sequencing methods, namely long polymerase chain reaction (PCR) and primer walking, to determine the complete mitochondrial DNA (mtDNA) sequence of Dugesia japonica and most of the mtDNA sequence of Dugesia ryukyuensis. The genome of D. japonica contained 36 genes including 12 of the 13 protein-coding genes characteristic of metazoan mitochondrial genomes, two ribosomal RNA genes, and 22 transfer RNA genes. The genome of D. ryukyuensis contained 33 genes, including 12 protein-coding genes, two ribosomal RNA genes, and 19 transfer RNA genes. The gene order of the mitochondrial genome from the Dugesia species showed no clear homology with either the Neodermata or other free-living Rhabditophora. This indicates that the platyhelminths exhibit great variability in mitochondrial gene order. This is the first complete sequence analysis of the mitochondrial genome of a free-living member of Rhabditophora, which will facilitate further studies on the population genetics and genomic evolution of the Platyhelminthes.

An alternative model for the early peopling of southern South America revealed by analyses of three mitochondrial DNA haplogroups.

After several years of research, there is now a consensus that America was populated from Asia through Beringia, probably at the end of the Pleistocene. But many details such as the timing, route(s), and origin of the first settlers remain uncertain. In the last decade genetic evidence has taken on a major role in elucidating the peopling of the Americas. To study the early peopling of South America, we sequenced the control region of mitochondrial DNA from 300 individuals belonging to indigenous populations of Chile and Argentina, and also obtained seven complete mitochondrial DNA sequences. We identified two novel mtDNA monophyletic clades, preliminarily designated B2l and C1b13, which together with the recently described D1g sub-haplogroup have locally high frequencies and are basically restricted to populations from the extreme south of South America. The estimated ages of D1g and B2l, about ∼15,000 years BP, together with their similar population dynamics and the high haplotype diversity shown by the networks, suggests that they probably appeared soon after the arrival of the first settlers and agrees with the dating of the earliest archaeological sites in South America (Monte Verde, Chile, 14,500 BP). One further sub-haplogroup, D4h3a5, appears to be restricted to Fuegian-Patagonian populations and reinforces our hypothesis of the continuity of the current Patagonian populations with the initial founders. Our results indicate that the extant native populations inhabiting South Chile and Argentina are a group which had a common origin, and suggest a population break between the extreme south of South America and the more northern part of the continent. Thus the early colonization process was not just an expansion from north to south, but also included movements across the Andes.

Complete nucleotide sequences of mitochondrial DNA of long-finned squid Loligo edulis

The complete nucleotide sequence of the mitochondrial genome of long-finned squid Loligo edulis forma kensaki (L. edulis f. kensaki, Teuthida: Myopsida) was determined. It contains 13 protein-coding genes, 12SrRNA, 16SrRNA, and the 22 tRNA genes, and three long noncoding regions. We also determined the mitochondrial genome nucleotide sequence of seasonal brood samples of L. edulis f. budo collected from the western part of the Sea of Japan in the autumn to winter seasons, which showed morphologic discrepancies with L. edulis f. kensaki. Comparison of the two complete sets of mitochondrial DNA data showed that the similarity of the two sequences was as high as 99.9 %, with only eight nucleotide substitutions in coding regions. The complete mitochondrial genome of Loligo edulis f. kensaki from Nagasaki Pref. is 17360 bp and L. edulis f. budo from the Shimane Pref. is 17351 bp. The nucleotide sequences and haplotype patterns in ND1 suggest that L. edulis f. kensaki and L. edulis f. budo share a single genetic background.

Mitochondrial genome variability within the Candida parapsilosis species complex

Candida parapsilosis species complex includes three closely related species, namely C. parapsilosis (sensu stricto), C. orthopsilosis, and C. metapsilosis. Unlike most other yeast lineages, members of this species complex possess a linear mitochondrial genome. Yet, its circularized mutant form was identified in strains of C. orthopsilosis and C. metapsilosis. To investigate the underlying variability, we performed comparative analyses of the complete mitochondrial DNA sequences in a collection of strains. Our results demonstrate that in contrast to C. parapsilosis and C. metapsilosis, C. orthopsilosis exhibits remarkably high nucleotide diversity whose pattern is consistent with intraspecific genetic exchange.

Mitochondrial genome sequence of the shining catfish (Pelteobagrus nitidus)

The complete mitochondrial DNA sequence of Pelteobagrus nitidus was determined using a PCR-based method. The total length of mitochondrial DNA is 16,532 bp. The contents of the P. nitidus mitochondrial genome are 13 protein-coding genes, two ribosomal RNA and 22 transfer RNA genes, and a non-coding control region. Base composition of the entire genome is A 31.72%, T 26.92%, C 26.45%, and G 14.91%, with an A+T (58.64%) rich feature as that of other vertebrate mitochondrial genome.

The complete mitochondrial genome sequence of Eimeria mitis (Apicomplexa: Coccidia)

In this study the complete mitochondrial DNA (mtDNA) sequence of Eimeria mitis was sequenced, and its gene contents and genome organizations were compared with that of other Eimeria spp. The complete mt genome sequence of E. mitis is 6407 bp in size. It consists of 3 protein-coding genes (cox1, cox3, and cytb), 12 gene fragments for the large subunit (LSU) rRNA, and 7 gene fragments for the small subunit (SSU) rRNA, but no transfer RNA genes, similar to that of Eimeria spp. The putative direction of translation for three genes (cox1, cox3, and cytb) was the same as those of six other Eimeria spp. The A+T content of the E. mitis mt genome was 67.30%. The E. mitis mt genome sequence provides novel mtDNA marker for studying the molecular epidemiology and population genetics of E. mitis and has implications for the molecular diagnosis of chicken coccidiosis caused by E. mitis.

Unique mitochondrial DNA in highly inbred feral cattle

The Chillingham herd of wild Northumbrian cattle remains viable despite over 300years of in-breeding and a near-homozygous nuclear genome. Here we report the complete mitochondrial DNA sequence using ultra-deep next generation sequencing. Random population sampling of ~10% of the extant herd identified a single mtDNA haplotype harbouring a unique bovine variant present in all other higher mammals (m.11789C/Y421H) which may contribute to their survival.

Phylogenetic studies of three sinipercid fishes (Perciformes: Sinipercidae) based on complete mitochondrial DNA sequences

The sinipercids are a group of 12 species of freshwater percoid fish endemic to East Asia and their phylogenetic placements have perplexed generations of taxonomists. We cloned and sequenced the complete mitochondrial DNA (mtDNA) of three sinipercid fishes (Siniperca chuatsi, S. kneri, and S. scherzeri) to characterize and compare their mitochondrial genomes. The mitochondrial genomes of S. chuatsi, S. kneri, and S. scherzeri were 16,496, 17,002, and 16,585 bp in length, respectively. The organization of the three mitochondrial genomes is similar to those reported from other fish mitochondrial genomes, which contains 37 genes (13 protein-coding genes, 2 ribosomal RNAs, and 22 transfer RNAs) and a major non-coding control region. Among the 13 protein-coding genes of all the three sinipercid fishes, three reading-frame overlaps were found on the same strand. There is an 81-bp tandem repeat cluster at the end of CSB-3 in the S. scherzeri control region. The complete mitochondrial genomes of the three sinipercids should be useful for the evolutionary studies of sinipercids and other vertebrate species.

Nonsynonymous variants in mt-Nd2, mt-Nd4, and mt-Nd5 are linked to effects on oxidative phosphorylation and insulin sensitivity in rat conplastic strains

Common inbred strains of the laboratory rat can be divided into four different mitochondrial DNA haplotype groups represented by the SHR, BN, LEW, and F344 strains. In the current study, we investigated the metabolic and hemodynamic effects of the SHR vs. LEW mitochondrial genomes by comparing the SHR to a new SHR conplastic strain, SHR-mt(LEW); these strains are genetically identical except for their mitochondrial genomes. Complete mitochondrial DNA (mtDNA) sequence analysis comparing the SHR and LEW strains revealed gene variants encoding amino acid substitutions limited to a single mitochondrial enzyme complex, NADH dehydrogenase (complex I), affecting subunits 2, 4, and 5. Two of the variants in the mt-Nd4 subunit gene are located close to variants known to be associated with exercise intolerance and diabetes mellitus in humans. No variants were found in tRNA or rRNA genes. These variants in mt-Nd2, mt-Nd4, and mt-Nd5 in the SHR-mt(LEW) conplastic strain were linked to reductions in oxidative and nonoxidative glucose metabolism in skeletal muscle. In addition, SHR-mt(LEW) conplastic rats showed increased serum nonesterified fatty acid levels and resistance to insulin stimulated incorporation of glucose into adipose tissue lipids. These results provide evidence that inherited variation in mitochondrial genes encoding respiratory chain complex I subunits, in the absence of variation in the nuclear genome and other confounding factors, can influence glucose and lipid metabolism when expressed on the nuclear genetic background of the SHR strain.

Oesophagostomum dentatum and Oesophagostomum quadrispinulatum: Characterization of the complete mitochondrial genome sequences of the two pig nodule worms

In the present study, the complete mitochondrial DNA (mtDNA) sequences of the pig nodule worm Oesophagostomum quadrispinulatum were determined for the first time, and the mt genome of Oesophagostomum dentatum from China was also sequenced for comparative analysis of their gene contents and genome organizations. The mtDNA sequences of O. dentatum China isolate and O. quadrispinulatum were 13,752 and 13,681bp in size, respectively. Each of the two mt genomes comprises 36 genes, including 12 protein-coding genes, two ribosomal RNA and 22 transfer RNA genes, but lacks the ATP synthetase subunit 8 gene. All genes are transcribed in the same direction and have a nucleotide composition high in A and T. The contents of A+T are 75.79% and 77.52% for the mt genomes of O. dentatum and O. quadrispinulatum, respectively. Phylogenetic analyses using concatenated amino acid sequences of the 12 protein-coding genes, with three different computational algorithms (maximum likelihood, maximum parsimony and Bayesian inference), all revealed that O. dentatum and O. quadrispinulatum represent distinct but closely-related species. These data provide novel and useful markers for studying the systematics, population genetics and molecular diagnosis of the two pig nodule worms.

Novel gene rearrangements in the mitochondrial genome of a webspinner, Aposthonia japonica (Insecta: Embioptera)

Webspinners (order Embioptera) are polyneopteran insects characterized by enlarged foretarsi with silk glands, whose silk is used to produce galleries in which the insects live gregariously. The phylogenetic position of webspinners has been debated. In the present study, an almost complete mitochondrial DNA (mtDNA) sequence of Embioptera is reported for the first time. The mtDNA of a webspinner, Aposthonia japonica , has the 13 protein-coding genes (PCGs) generally found in metazoan mtDNA sequences. There is a translocation of a large region including atp6, atp8, cox3, nad3, and nad5 as well as a duplication of the 12S rRNA gene. The rearrangement does not seem to affect nucleotide composition, although amino acid composition in some parts of the mtDNA is biased compared with other Polyneoptera species. Based on phylogenetic analyses using nucleotide sequences of all PCGs concatenated with two rRNA genes and the amino acid sequences of all PCGs, A. japonica is sister to Verophasmatodea, a suborder of typical stick and leaf insects.

Complete mitochondrial DNA sequence analysis in two southern Chinese pedigrees with Leber hereditary optic neuropathy revealed secondary mutations along with the primary mutation.

To investigate mitochondrial factors associated with Leber hereditary optic neuropathy (LHON) through complete sequencing and analysis of the mitochondrial genome of Chinese patients with this disease. Two unrelated southern Chinese families with LHON and 10 matched healthy controls were recruited, and their entire mitochondrial DNA (mtDNA) was amplified and sequenced with the universal M13 primer. Then DNA sequence analysis and variation identification were perfomed by DNAssist and Chromas 2 software and compared with authoritative databases such as Mitomap. Mutational analysis of mtDNA in these two Chinese pedigrees revealed one common LHON-associated mutation, G11778A (Arg→His), in the MT-ND4 gene. In addition, there were two secondary mutations in Pedigree 1: C3497T (Ala→Val), and C3571T (Leu→Phe) in the MT-ND1 gene, which have not been reported; and two secondary mutations occurred in Pedigree 2: A10398G (Thr→Ala) in the MT-ND3 gene, and T14502C (Ile→Val) in the MT-ND6 gene. Three polymorphisms, A73G, G94A and A263G in the mtDNA control region, were also found. Our study confirmed that the known MT-ND4*G11778A mutation is the most significant cause of LHON. The C3497T and C3571T mutations in Pedigree 1 were also both at hot-spots of MT-ND1; they may affect the respiratory chain in coordination with the primary mutation G11778A. In Pedigree 2, the two secondary mutations A10398G of MT-ND3 and T14502C of MT-ND6 may influence mitochondrial respiratory complex I, leading to the mitochondrial respiratory chain dysfunction which results in optic atrophy together with G11778A. Therefore, not only the common primary LHON mutation is responsible for the visual atrophy, but other secondary mtDNA mutations should also be considered when giving genetic counseling.

Diagnosis of mitochondrial disorders applying massive pyrosequencing

Mitochondrial disorders are a frequent cause of neurological disability affecting children and adults. Traditionally, molecular diagnosis of mitochondrial diseases was mostly accomplished by the use of Sanger sequencing and PCR-RFLP. However, there are particular drawbacks associated with the use of these methods. Recent multidisciplinary advances have led to new sequencing methods that may overcome these limitations. Our goal was to explore the use of a next generation sequencing platform in the molecular diagnosis of mitochondrial diseases reporting our findings in adult patients that present with a clinical-pathological diagnosis of a mitochondrial encephalomyopathy. Complete genomic sequences of mitochondrial DNA were obtained by 454 massive pyrosequencing from blood samples. The analysis of these sequences allowed us to identify two diagnostic pathogenic mutations and 74 homoplasmic polymorphisms, useful for obtaining high-resolution mitochondrial haplogroups. In summary, molecular diagnosis of mitochondrial disorders could be efficiently done from readily accessible samples, such as blood, with the use of a new sequencing platform.