scholarly journals Long-read sequencing reveals atypical mitochondrial genome structure in a New Zealand marine isopod

2022 ◽  
Vol 9 (1) ◽  
Author(s):  
William S. Pearman ◽  
Sarah J. Wells ◽  
James Dale ◽  
Olin K. Silander ◽  
Nikki E. Freed
Keyword(s):  
New Zealand ◽  
Mitochondrial Genome ◽  
Dna Sequencing ◽  
Recent Work ◽  
Genome Structure ◽  
Mitochondrial Genomes ◽  
Short Read ◽  
Mitochondrial Structure ◽  
Evolutionary Origins ◽  
Long Read

Most animal mitochondrial genomes are small, circular and structurally conserved. However, recent work indicates that diverse taxa possess unusual mitochondrial genomes. In Isopoda , species in multiple lineages have atypical and rearranged mitochondrial genomes. However, more species of this speciose taxon need to be evaluated to understand the evolutionary origins of atypical mitochondrial genomes in this group. In this study, we report the presence of an atypical mitochondrial structure in the New Zealand endemic marine isopod, Isocladus armatus. Data from long- and short-read DNA sequencing suggest that I. armatus has two mitochondrial chromosomes. The first chromosome consists of two mitochondrial genomes that have been inverted and fused together in a circular form, and the second chromosome consists of a single mitochondrial genome in a linearized form. This atypical mitochondrial structure has been detected in other isopod lineages, and our data from an additional divergent isopod lineage (Sphaeromatidae) lends support to the hypothesis that atypical structure evolved early in the evolution of Isopoda . Additionally, we find that an asymmetrical site previously observed across many species within Isopoda is absent in I. armatus , but confirm the presence of two asymmetrical sites recently reported in two other isopod species.

scholarly journals Long read sequencing reveals atypical mitochondrial genome structure in a New Zealand marine isopod

2021 ◽  
Author(s):  
William S Pearman ◽  
Sarah J Wells ◽  
James Dale ◽  
Olin K Silander ◽  
Nikki E Freed
Keyword(s):  
New Zealand ◽  
Mitochondrial Genome ◽  
Dna Sequencing ◽  
Recent Work ◽  
Genome Structure ◽  
Mitochondrial Genomes ◽  
Short Read ◽  
Mitochondrial Structure ◽  
Evolutionary Origins ◽  
Long Read

Most animal mitochondrial genomes are small, circular, and structurally conserved. However, recent work indicates that diverse taxa possess unusual mitochondrial genomes. In Isopoda, species in multiple lineages have atypical and rearranged mitochondrial genomes. However, more species of this speciose taxon need to be evaluated to understand the evolutionary origins of atypical mitochondrial genomes in this group. In this study, we report the presence of an atypical mitochondrial structure in the New Zealand endemic marine isopod, Isocladus armatus. Data from long and short read DNA sequencing, suggests that I. armatus has two mitochondrial chromosomes. The first chromosome consists of two mitochondrial genomes that have been inverted and fused together in a circular form, and the second chromosome consists of a single mitochondrial genome in a linearized form. This atypical mitochondrial structure has been detected in other isopod lineages, and our data from an additional divergent isopod lineage (Sphaeromatidae) lends support to the hypothesis that atypical structure evolved early in the evolution of Isopoda. Additionally, we find that a heteroplasmic site previously observed across many species within Isopoda is absent in I. armatus, but confirm the presence of two heteroplasmic sites recently reported in two other isopod species.

scholarly journals Mitochondrial genome evolution in pelagophyte algae

2021 ◽  
Author(s):  
Shannon J Sibbald ◽  
Maggie Lawton ◽  
John M Archibald
Keyword(s):  
Mitochondrial Genome ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
23S Rrna ◽  
Mitochondrial Genomes ◽  
Trna Genes ◽  
Unique Region ◽  
Long Read ◽  
Genomic Studies ◽  
Aureoumbra Lagunensis

Abstract The Pelagophyceae are marine stramenopile algae that include Aureoumbra lagunensis and Aureococcus anophagefferens, two microbial species notorious for causing harmful algal blooms. Despite their ecological significance, relatively few genomic studies of pelagophytes have been carried out. To improve understanding of the biology and evolution of pelagophyte algae, we sequenced complete mitochondrial genomes for A. lagunensis (CCMP1510), Pelagomonas calceolata (CCMP1756) and five strains of A. anophagefferens (CCMP1707, CCMP1708, CCMP1850, CCMP1984 and CCMP3368) using Nanopore long-read sequencing. All pelagophyte mitochondrial genomes assembled into single, circular mapping contigs between 39,376 base-pairs (bp) (P. calceolata) and 55,968 bp (A. lagunensis) in size. Mitochondrial genomes for the five A. anophagefferens strains varied slightly in length (42,401 bp—42,621 bp) and were 99.4%-100.0% identical. Gene content and order was highly conserved between the A. anophagefferens and P. calceolata genomes, with the only major difference being a unique region in A. anophagefferens containing DNA adenine and cytosine methyltransferase (dam/dcm) genes that appear to be the product of lateral gene transfer from a prokaryotic or viral donor. While the A. lagunensis mitochondrial genome shares seven distinct syntenic blocks with the other pelagophyte genomes, it has a tandem repeat expansion comprising ∼40% of its length, and lacks identifiable rps19 and glycine tRNA genes. Laterally acquired self-splicing introns were also found in the 23S rRNA (rnl) gene of P. calceolata and the coxI gene of the five A. anophagefferens genomes. Overall, these data provide baseline knowledge about the genetic diversity of bloom-forming pelagophytes relative to non-bloom-forming species.

scholarly journals Revealing the high variability on nonconserved core and mobile elements of Austropuccinia psidii and other rust mitochondrial genomes

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248054
Author(s):  
Jaqueline Raquel de Almeida ◽  
Diego Mauricio Riaño Pachón ◽  
Livia Maria Franceschini ◽  
Isaneli Batista dos Santos ◽  
Jessica Aparecida Ferrarezi ◽  
...  
Keyword(s):  
Mitochondrial Genome ◽  
Transmembrane Protein ◽  
Genome Structure ◽  
Rust Fungi ◽  
Mitochondrial Genomes ◽  
Phylogenomic Analysis ◽  
The Core ◽  
Mtdna Sequence ◽  
Austropuccinia Psidii

Mitochondrial genomes are highly conserved in many fungal groups, and they can help characterize the phylogenetic relationships and evolutionary biology of plant pathogenic fungi. Rust fungi are among the most devastating diseases for economically important crops around the world. Here, we report the complete sequence and annotation of the mitochondrial genome of Austropuccinia psidii (syn. Puccinia psidii), the causal agent of myrtle rust. We performed a phylogenomic analysis including the complete mitochondrial sequences from other rust fungi. The genome composed of 93.299 bp has 73 predicted genes, 33 of which encoded nonconserved proteins (ncORFs), representing almost 45% of all predicted genes. A. psidii mtDNA is one of the largest rust mtDNA sequenced to date, most likely due to the abundance of ncORFs. Among them, 33% were within intronic regions of diverse intron groups. Mobile genetic elements invading intron sequences may have played significant roles in size but not shaping of the rust mitochondrial genome structure. The mtDNAs from rust fungi are highly syntenic. Phylogenetic inferences with 14 concatenated mitochondrial proteins encoded by the core genes placed A. psidii according to phylogenetic analysis based on 18S rDNA. Interestingly, cox1, the gene with the greatest number of introns, provided phylogenies not congruent with the core set. For the first time, we identified the proteins encoded by three A. psidii ncORFs using proteomics analyses. Also, the orf208 encoded a transmembrane protein repressed during in vitro morphogenesis. To the best of our knowledge, we presented the first report of a complete mtDNA sequence of a member of the family Sphaerophragmiacea.

scholarly journals Generating closed bacterial genomes from long-read nanopore sequencing of microbiomes

2018 ◽  
Author(s):  
Eli L. Moss ◽  
Ami S. Bhatt
Keyword(s):  
Genome Structure ◽  
Nanopore Sequencing ◽  
Bacterial Genomes ◽  
Human Gut ◽  
Healthy Human ◽  
Short Read ◽  
Long Read ◽  
Efficient Recovery

AbstractWe present the first method for efficient recovery of complete, closed genomes directly from microbiomes using nanopore long-read sequencing and assembly. We apply our approach to three healthy human gut communities and compare results to short read and read cloud approaches. We obtain nine finished genomes including the first reported closed genome of Prevotella copri, an organism with highly repetitive genome structure prevalent in non-western human gut microbiomes.

scholarly journals Largest Complete Mitochondrial Genome of a Gymnosperm, Sitka Spruce (Picea sitchensis), Indicates Complex Physical Structure

2019 ◽  
Author(s):  
Shaun D. Jackman ◽  
Lauren Coombe ◽  
René L. Warren ◽  
Heather Kirk ◽  
Eva Trinh ◽  
...  
Keyword(s):  
Mitochondrial Genome ◽  
Active Sites ◽  
Complete Mitochondrial Genome ◽  
Genome Structure ◽  
Sitka Spruce ◽  
Physical Structure ◽  
Picea Sitchensis ◽  
Mitochondrial Genomes ◽  
Long Reads ◽  
Branching Points

AbstractPlant mitochondrial genomes vary widely in size. Although many plant mitochondrial genomes have been sequenced and assembled, the vast majority are of angiosperms, and few are of gymnosperms. Most plant mitochondrial genomes are smaller than a megabase, with a few notable exceptions. We have sequenced and assembled the 5.5 Mbp mitochondrial genome of Sitka spruce (Picea sitchensis), the largest complete mitochondrial genome of a gymnosperm. We sequenced the whole genome using Oxford Nanopore MinION, and then identified contigs of mitochondrial origin assembled from these long reads. The assembly graph shows a multipartite genome structure, composed of one smaller 168 kbp circular segment of DNA, and a larger 5.4 Mbp component with a branching structure. The assembly graph gives insight into a putative complex physical genome structure, and its branching points may represent active sites of recombination.

scholarly journals Long-read assemblies reveal structural diversity in genomes of organelles - an example with Acacia pycnantha

2020 ◽  
Author(s):  
Anna E. Syme ◽  
Todd G.B. McLay ◽  
Frank Udovicic ◽  
David J. Cantrill ◽  
Daniel J. Murphy
Keyword(s):  
Mitochondrial Genome ◽  
Chloroplast Genome ◽  
De Novo ◽  
Genomic Structure ◽  
Structural Diversity ◽  
Mitochondrial Genomes ◽  
Long Reads ◽  
Organelle Genomes ◽  
Long Read ◽  
Assembly Algorithms

AbstractAlthough organelle genomes are typically represented as single, static, circular molecules, there is evidence that the chloroplast genome exists in two structural haplotypes and that the mitochondrial genome can display multiple circular, linear or branching forms. We sequenced and assembled chloroplast and mitochondrial genomes of the Golden Wattle, Acacia pycnantha, using long reads, iterative baiting to extract organelle-only reads, and several assembly algorithms to explore genomic structure. Using a de novo assembly approach agnostic to previous hypotheses about structure, we found different assemblies revealed contrasting arrangements of genomic segments; a hypothesis supported by mapped reads spanning alternate paths.

The plant mitochondrial genome: homologous recombination as a mechanism for generating heterogeneity

1988 ◽  
Vol 319 (1193) ◽  
pp. 149-163 ◽  
Keyword(s):  
Mitochondrial Dna ◽  
Homologous Recombination ◽  
Mitochondrial Genome ◽  
Higher Plants ◽  
Genome Structure ◽  
Rapid Evolution ◽  
Mitochondrial Genomes ◽  
Base Sequence ◽  
Plant Mitochondrial Genome ◽  
Organelle Genomes

The mitochondrial genomes of higher plants are among the largest and most complex organelle genomes described. They are generally multicircular or partly linear; in some species, extrachromosomal plasmids are present. It is proposed that inter- and intramolecular homologous recombination can account for the diversity of the observed genome organizations. The ability of mitochondria to fuse establishes a panmictic mitochondrial DNA population which is in recombinational equilibrium. It is suggested that this suppresses the base mutation rate, and unequal partitioning of the cytoplasm during cell division can lead to the rapid evolution of mitochondrial genome structure. This contrasts with the observed rates of base-sequence and genome evolution in chloroplasts. This difference can be accounted for solely by the inability of chloroplasts to fuse, thereby preventing chloroplast genome panmixis.

scholarly journals Assembly of the Mitochondrial Genome in the Campanulaceae Family Using Illumina Low-Coverage Sequencing

Genes ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 383 ◽  
Author(s):  
Hyun-Oh Lee ◽  
Ji-Weon Choi ◽  
Jeong-Ho Baek ◽  
Jae-Hyeon Oh ◽  
Sang-Choon Lee ◽  
...  
Keyword(s):  
Mitochondrial Genome ◽  
Dna Sequencing ◽  
De Novo ◽  
Genome Structure ◽  
Sequencing Data ◽  
Phylogenetic Characterization ◽  
Low Coverage ◽  
Paired End Sequencing ◽  
Circular Chromosomes

Platycodon grandiflorus (balloon flower) and Codonopsis lanceolata (bonnet bellflower) are important herbs used in Asian traditional medicine, and both belong to the botanical family Campanulaceae. In this study, we designed and implemented a de novo DNA sequencing and assembly strategy to map the complete mitochondrial genomes of the first two members of the Campanulaceae using low-coverage Illumina DNA sequencing data. We produced a total of 28.9 Gb of paired-end sequencing data from the genomic DNA of P. grandiflorus (20.9 Gb) and C. lanceolata (8.0 Gb). The assembled mitochondrial genome of P. grandiflorus was found to consist of two circular chromosomes; the master circle contains 56 genes, and the minor circle contains 42 genes. The C. lanceolata mitochondrial genome consists of a single circle harboring 54 genes. Using a comparative genome structure and a pattern of repeated sequences, we show that the P. grandiflorus minor circle resulted from a recombination event involving the direct repeats of the master circle. Our dataset will be useful for comparative genomics and for evolutionary studies, and will facilitate further biological and phylogenetic characterization of species in the Campanulaceae.

scholarly journals Mitochondrial sequences or Numts – By-catch differs between sequencing methods

2019 ◽  
Author(s):  
Hannes Becher ◽  
Richard A Nichols
Keyword(s):  
Mitochondrial Dna ◽  
Mitochondrial Genome ◽  
Nuclear Genome ◽  
Short Read ◽  
Ancestral Sequences ◽  
Mtdna Sequence ◽  
Long Read ◽  
Data Yield ◽  
By Catch ◽  
Numt Sequence

AbstractNuclear inserts derived from mitochondrial DNA (Numts) encode valuable information. Being mostly non-functional, and accumulating mutations more slowly than mitochondrial sequence, they act like molecular fossils – they preserve information on the ancestral sequences of the mitochondrial DNA. In addition, changes to the Numt sequence since their insertion into the nuclear genome carry information about the nuclear phylogeny. These attributes cannot be reliably exploited if Numt sequence is confused with the mitochondrial genome (mtDNA). The analysis of mtDNA would be similarly compromised by any confusion, for example producing misleading results in DNA barcoding that used mtDNA sequence. We propose a method to distinguish Numts from mtDNA, without the need for comprehensive assembly of the nuclear genome or the physical separation of organelles and nuclei. It exploits the different biases of long and short-read sequencing. We find that short-read data yield mainly mtDNA sequences, whereas long-read sequencing strongly enriches for Numt sequences. We demonstrate the method using genome-skimming (coverage < 1x) data obtained on Illumina short-read and PacBio long-read technology from DNA extracted from six grasshopper individuals. The mitochondrial genome sequences were assembled from the short-read data despite the presence of Numts. The PacBio data contained a much higher proportion of Numt reads (over 16-fold), making us caution against the use of long-read methods for studies using mitochondrial loci. We obtained two estimates of the genomic proportion of Numts. Finally, we introduce “tangle plots”, a way of visualising Numt structural rearrangements and comparing them between samples.

scholarly journals CaBagE: A Cas9-based Background Elimination strategy for targeted, long-read DNA sequencing

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0241253
Author(s):  
Amelia D. Wallace ◽  
Thomas A. Sasani ◽  
Jordan Swanier ◽  
Brooke L. Gates ◽  
Jeff Greenland ◽  
...  
Keyword(s):  
Dna Sequencing ◽  
Tandem Repeats ◽  
Short Read ◽  
Background Elimination ◽  
Sequencing Technologies ◽  
Long Reads ◽  
Long Read ◽  
Repeat Expansions ◽  
Sequencing Platforms ◽  
Als Patients

A substantial fraction of the human genome is difficult to interrogate with short-read DNA sequencing technologies due to paralogy, complex haplotype structures, or tandem repeats. Long-read sequencing technologies, such as Oxford Nanopore’s MinION, enable direct measurement of complex loci without introducing many of the biases inherent to short-read methods, though they suffer from relatively lower throughput. This limitation has motivated recent efforts to develop amplification-free strategies to target and enrich loci of interest for subsequent sequencing with long reads. Here, we present CaBagE, a method for target enrichment that is efficient and useful for sequencing large, structurally complex targets. The CaBagE method leverages the stable binding of Cas9 to its DNA target to protect desired fragments from digestion with exonuclease. Enriched DNA fragments are then sequenced with Oxford Nanopore’s MinION long-read sequencing technology. Enrichment with CaBagE resulted in a median of 116X coverage (range 39–416) of target loci when tested on five genomic targets ranging from 4-20kb in length using healthy donor DNA. Four cancer gene targets were enriched in a single reaction and multiplexed on a single MinION flow cell. We further demonstrate the utility of CaBagE in two ALS patients with C9orf72 short tandem repeat expansions to produce genotype estimates commensurate with genotypes derived from repeat-primed PCR for each individual. With CaBagE there is a physical enrichment of on-target DNA in a given sample prior to sequencing. This feature allows adaptability across sequencing platforms and potential use as an enrichment strategy for applications beyond sequencing. CaBagE is a rapid enrichment method that can illuminate regions of the ‘hidden genome’ underlying human disease.

Sign in / Sign up

Export Citation Format

Share Document