scholarly journals Using high-resolution annotation of insect mitochondrial DNA to decipher tandem repeats in the control region

2018 ◽  
Author(s):  
Ji Haishuo ◽  
Xu Xiaofeng ◽  
Jin Xiufeng ◽  
Cheng Zhi ◽  
jin Hong ◽  
...  

In this study, we used a small RNA sequencing (sRNA-seq) based method to annotate the mitochondrial genome of the insect Erthesina fullo Thunberg at 1 bp resolution. Most of the new annotations were consistent with the previous annotations which were obtained using PacBio full-length transcripts. Two important findings are that animals transcribe both entire strands of mitochondrial genomes and the tandem repeat in the control region of the E. fullo mitochondrial genome contains the repeated Transcription Initiation Sites (TISs) of the H-strand. In addition, we found that the copy numbers of tandem repeats showed a great diversity within an individual, enriching the fundamental knowledge of mitochondrial biology. This sRNA-seq based method uses 5′ and 3′ end small RNAs to annotate nuclear non-coding and mitochondrial genes at 1 bp resolution and can also be used to identify new steady-state RNAs, particularly long non-coding RNAs (lncRNAs). Animal mitochondrial genomes containing one control region only encode two steady-state lncRNAs, which are the Mitochondrial D-loop 1 (MDL1) and its antisense gene (MDL1AS), while all other reported mitochondrial lncRNAs could be degraded fragments of transient RNAs or random breaks during experimental processing. The high-resolution annotations of mitochondrial genomes can be used to study the phylogenetics and molecular evolution of animals or to investigate mitochondrial gene transcription, RNA processing, RNA maturation and several other related topics.

2018 ◽  
Author(s):  
Zhichao Yan ◽  
Qi Fang ◽  
Yu Tian ◽  
Fang Wang ◽  
Xuexin Chen ◽  
...  

AbstractChalcidoidea (chalcidoid wasps) are an abundant and megadiverse insect group with both ecological and economical importance. Here we report a complete mitochondrial genome in Chalcidoidea from Pteromalus puparum (Pteromalidae). Eight tandem repeats followed by 6 reversed repeats were detected in its 3,308 bp control region. This long and complex control region may explain failures of amplifying and sequencing of complete mitochondrial genomes in some chalcidoids. In addition to 37 typical mitochondrial genes, an extra identical isoleucine tRNA (trnI) was detected. We speculate this recent mitochondrial gene duplication indicates that gene arrangements in chalcidoids are ongoing. A comparison among available chalcidoid mitochondrial genomes, reveals rapid gene order rearrangements overall, and high substitution rate in P. puparum. In addition, we identified 24 nuclear sequences of mitochondrial origin (NUMTs) in P. puparum, summing up to 9,989 bp, with 3,617 bp of these NUMTs originating from mitochondrial coding regions. NUMTs abundance in P. puparum is only one-twelfth of that in its relative, Nasonia vitripennis. Based on phylogenetic analysis, we provide evidence that a faster nuclear degradation rate contributes to the reduced NUMT numbers in P. puparum. Overall, our study shows unusually high rates of mitochondrial evolution and considerable variation in NUMT accumulation in Chalcidoidea.


RNA Biology ◽  
2019 ◽  
Vol 16 (6) ◽  
pp. 830-837 ◽  
Author(s):  
Haishuo Ji ◽  
Xiaofeng Xu ◽  
Xiufeng Jin ◽  
Hong Yin ◽  
Jianxun Luo ◽  
...  

Genetics ◽  
1988 ◽  
Vol 120 (3) ◽  
pp. 707-712
Author(s):  
B C Hyman ◽  
J L Beck ◽  
K C Weiss

Abstract The nematode Romanomermis culicivorax, an obligate mosquito parasite, possesses a 26 kilobase (kb) mitochondrial genome. The unusually large size is due to transcriptionally active DNA sequences present as 3.0 kb direct tandem repeats and as inverted portions of the repeating unit located elsewhere in the mitochondrial DNA (mtDNA). The genome rearrangements involved in establishing this unusual sequence organization may have dramatically altered conventional mitochondrial gene order. Genes for subunits of the cytochrome c oxidase complex (COI and COII) are normally closely linked in animal mtDNAs, but are separated by approximately 8 kb in this mitochondrial genome.


Genes ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 607
Author(s):  
Nataliya Kozhukhar ◽  
Sunil Mitta ◽  
Mikhail F. Alexeyev

The COS-7 cell line is a workhorse of virology research. To expand this cell line’s utility and to enable studies on mitochondrial DNA (mtDNA) transcription and replication, we determined the complete nucleotide sequence of its mitochondrial genome by Sanger sequencing. In contrast to other available mtDNA sequences from Chlorocebus aethiops, the mtDNA of the COS-7 cell line was found to contain a variable number of perfect copies of a 108 bp unit tandemly repeated in the control region. We established that COS-7 cells are heteroplasmic with at least two variants being present: with four and five repeat units. The analysis of the mitochondrial genome sequences from other primates revealed that tandem repeats are absent from examined mtDNA control regions of humans and great apes, but appear in lower primates, where they are present in a homoplasmic state. To our knowledge, this is the first report of mtDNA length heteroplasmy in primates.


2016 ◽  
Vol 64 (2) ◽  
pp. 117 ◽  
Author(s):  
Daniel J. Schmidt ◽  
Brittany Brockett ◽  
Thomas Espinoza ◽  
Marilyn Connell ◽  
Jane M. Hughes

Elusor macrurus is an endangered short-necked turtle restricted to the Mary River catchment in south-eastern Queensland. Shotgun sequencing of genomic DNA was used to generate a complete mitochondrial genome sequence for E. macrurus using the Illumina MiSeq platform. The mitogenome is 16 499 base pairs (bp) long with 37 genes arranged in the typical vertebrate order and a relatively short 918-bp control region, which does not feature extensive tandem repeats as observed in some turtles. Primers were designed to amplify a 1270-bp region that includes 81% of the typically hypervariable control region. Two haplotypes were detected in a sample of 22 wild-caught individuals from eight sites across its natural range. The Mary River turtle is a species with low mtDNA nucleotide variability relative to other Chelidae. The combination of a very restricted distribution and dramatic reduction in population size due to exploitation for the pet trade are the conditions likely to have led to very low mtDNA variability in this endangered species.


Genome ◽  
2009 ◽  
Vol 52 (4) ◽  
pp. 299-307 ◽  
Author(s):  
Grzegorz Bartoszewski ◽  
Piotr Gawronski ◽  
Marek Szklarczyk ◽  
Henk Verbakel ◽  
Michael J. Havey

Cucumber ( Cucumis sativus ) has one of the largest mitochondrial genomes known among all eukaryotes, due in part to the accumulation of short 20 to 60 bp repetitive DNA motifs. Recombination among these repetitive DNAs produces rearrangements affecting organization and expression of mitochondrial genes. To more efficiently identify rearrangements in the cucumber mitochondrial DNA, we built two nonoverlapping 800 and 220 kb BAC contigs and assigned major mitochondrial genes to these BACs. Polymorphism carried on the largest BAC contig was used to confirm paternal transmission. Mitochondrial genes were distributed across BACs and physically distant, although occasional clustering was observed. Introns in the nad1, nad4, and nad7 genes were larger than those reported in other plants, due in part to accumulation of short repetitive DNAs and indicating that increased intron sizes contributed to mitochondrial genome expansion in cucumber. Mitochondrial genes atp6 and atp9 are physically close to each other and cotranscribed. These physical contigs will be useful for eventual sequencing of the cucumber mitochondrial DNA, which can be exploited to more efficiently screen for unique rearrangements affecting mitochondrial gene expression.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3692 ◽  
Author(s):  
Fabrizio Ghiselli ◽  
Liliana Milani ◽  
Mariangela Iannello ◽  
Emanuele Procopio ◽  
Peter L. Chang ◽  
...  

Despite the large number of animal complete mitochondrial genomes currently available in public databases, knowledge about mitochondrial genomics in invertebrates is uneven. This paper reports, for the first time, the complete mitochondrial genome of the grooved carpet shell,Ruditapes decussatus, also known as the European clam.Ruditapes decussatusis morphologically and ecologically similar to the Manila clamRuditapes philippinarum, which has been recently introduced for aquaculture in the very same habitats ofRuditapes decussatus, and that is replacing the native species. Currently the production of the European clam is almost insignificant, nonetheless it is considered a high value product, and therefore it is an economically important species, especially in Portugal, Spain and Italy. In this work we: (i) assembledRuditapes decussatusmitochondrial genome from RNA-Seq data, and validated it by Sanger sequencing; (ii) analyzed and characterized theRuditapes decussatusmitochondrial genome, comparing its features with those of other venerid bivalves; (iii) assessed mitochondrial sequence polymorphism (SP) and copy number variation (CNV) of tandem repeats across 26 samples. Despite using high-throughput approaches we did not find evidence for the presence of two sex-linked mitochondrial genomes, typical of the doubly uniparental inheritance of mitochondria, a phenomenon known in ∼100 bivalve species. According to our analyses,Ruditapes decussatusis more genetically similar to species of the Genus Paphia than to the congenericRuditapes philippinarum, a finding that bolsters the already-proposed need of a taxonomic revision. We also found a quite low genetic variability across the examined samples, with few SPs and little variability of the sequences flanking the control region (Largest Unassigned Regions (LURs). Strikingly, although we found low nucleotide variability along the entire mitochondrial genome, we observed high levels of length polymorphism in the LUR due to CNV of tandem repeats, and even a LUR length heteroplasmy in two samples. It is not clear if the lack of genetic variability in the mitochondrial genome ofRuditapes decussatusis a cause or an effect of the ongoing replacement ofRuditapes decussatuswith the invasiveRuditapes philippinarum, and more analyses, especially on nuclear sequences, are required to assess this point.


2018 ◽  
Author(s):  
Shantanu Kundu ◽  
Vikas Kumar ◽  
Kaomud Tyagi ◽  
Rajasree Chakraborty ◽  
Iftikar Rahaman ◽  
...  

Complete mitochondrial genomes of Indian tent turtle, Pangshura tentoria was sequenced and annotated as 16,657 bp in length. This first assembly was encoded by 37 genes: 13 protein coding genes (PCGs), 22 transfer RNA (tRNAs), two ribosomal RNA (rRNAs) as similar to the typical vertebrate mitochondrial gene arrangement. The complete mitogenome has a base composition of A (33.30%), G (13.54%), C (27%), and T (26.13%). Most of the genes were encoded on major strand, except for the eight tRNAs and one PCG (nad6). Almost all PCGs were starting with an ATG initiation codon, except for cytochrome oxidase subunit 1 (cox1) with ‘GTG’ and NADH dehydrogenase subunit 5 (nad5) with ‘ATA’. The typical termination codons, ‘TAA’ and ‘AGA’ has been observed in NADH dehydrogenase subunit 4l (nad4l) and NADH dehydrogenase subunit 6 (nad6) respectively; and others were used incomplete stop codons. The Relative Synonymous Codon Usage (RSCU) analysis revealed the maximum abundance of Alanine, Isoleucine, Leucine, and Threonine in P. tentoria. Codon distribution per thousand codon (CDsPT) values for all the amino acids showed the maximum values were present for Leucine in all geoemydid turtles. Further, the PCGs showed non-synonymous (Ka)/synonymous (Ks) values were <1 that indicated a strong negative selection among the studied species. The tRNAs were folded into classic clover-leaf secondary structures, except for trnS (GCT), lacking of the conventional DHU arm or stem. Further, the 10 tRNAs showed G-T mismatches and forming weak bonds. In the control region (CR) of P. tentoria, a single tandem repeat of eight base pairs (TTCTCTTT) was resulted with two copy numbers. The comparative study of CR with other geoemydid turtles revealed the numbers of tandem repeats were frequent in the 3´ end and structural characteristic were species-specific. The Maximum Likelihood (ML) phylogeny showed 32 geoemydid turtles were clustered distinctly with high bootstrap support and congruent with the previous phylogenetic hypothesis. Further, the representative mitogenome sequences of other family/suborder were depicted discrete clades in the ML tree. The study argued the complete mitochondrial genome sequence of P. tentoria and comparative mitochondriomics of geoemydid turtles would be useful for further phylogenetic reconciliation and evolutionary research.


2018 ◽  
Author(s):  
Sergio N Stampar ◽  
Michael B Broe ◽  
Jason Macrander ◽  
Adam M Reitzel ◽  
Marymegan Daly

Sequences and structural attributes of mitochondrial genomes have played a key role in the clarification of relationships among Cnidaria, a key phylum of early-diverging animals. Among the major lineages of Cnidaria, Ceriantharia ("tube anemones") remains one of the most enigmatic groups in terms of its phylogenetic position. We sequenced the mitochondrial genomes of two ceriantharians to see whether the complete organellar genome would provide more support for the phylogenetic placement of Ceriantharia. For both ceriantharian species studied, the mitochondrial gene sequences could not be assembled into a circular genome. Instead, our analyses suggest both species have fragmented mitochondrial genomes consisting of multiple linear fragments. Linear mitogenomes are characteristic of members of Medusozoa, one of the major lineages of Cnidaria, but are unreported for Anthozoa, which includes the Ceriantharia. The number of fragments and the variation in gene order between species is much greater in Ceriantharia than among Medusozoa. The novelty of the mitogenomic structure in Ceriantharia highlights the distinctiveness of this lineage but, because it appears to be both unique to and diverse within Ceriantharia, it is uninformative about the phylogenetic position of Ceriantharia relative to other anthozoan groups.


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