scholarly journals Picopore: A tool for reducing the storage size of Oxford Nanopore Technologies datasets without loss of functionality

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 227 ◽  
Author(s):  
Scott Gigante
Keyword(s):  
Data Storage ◽  
Data Generation ◽  
Biologically Relevant ◽  
Sequencing Technologies ◽  
Long Term Storage ◽  
Oxford Nanopore ◽  
Long Read ◽  
Oxford Nanopore Technologies ◽  
Term Storage

Oxford Nanopore Technologies' (ONT) MinION and PromethION long-read sequencing technologies are emerging as genuine alternatives to established Next-Generation Sequencing technologies. A combination of the highly redundant file format and a rapid increase in data generation have created a significant problem both for immediate data storage on MinION-capable laptops, and for long-term storage on lab data servers.  We developed Picopore, a software suite offering three methods of compression. Picopore's lossless and deep lossless methods provide a 25% and 44% average reduction in size, respectively, without removing any data from the files. Picopore's raw method provides an 88% average reduction in size, while retaining biologically relevant data for the end-user. All methods have the capacity to run in real-time in parallel to a sequencing run, reducing demand for both immediate and long-term storage space.

scholarly journals Picopore: A tool for reducing the storage size of Oxford Nanopore Technologies datasets without loss of functionality

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 227 ◽  
Author(s):  
Scott Gigante
Keyword(s):  
Data Storage ◽  
Data Generation ◽  
Biologically Relevant ◽  
Sequencing Technologies ◽  
Long Term Storage ◽  
Oxford Nanopore ◽  
Long Read ◽  
Oxford Nanopore Technologies ◽  
Term Storage

Oxford Nanopore Technologies' (ONT's) MinION and PromethION long-read sequencing technologies are emerging as genuine alternatives to established Next-Generation Sequencing technologies. A combination of the highly redundant file format and a rapid increase in data generation have created a significant problem both for immediate data storage on MinION-capable laptops, and for long-term storage on lab data servers. We developed Picopore, a software suite offering three methods of compression. Picopore's lossless and deep lossless methods provide a 25% and 44% average reduction in size, respectively, without removing any data from the files. Picopore's raw method provides an 88% average reduction in size, while retaining biologically relevant data for the end-user. All methods have the capacity to run in real-time in parallel to a sequencing run, reducing demand for both immediate and long-term storage space.

scholarly journals Picopore: A tool for reducing the storage size of Oxford Nanopore Technologies datasets without loss of functionality

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 227 ◽  
Author(s):  
Scott Gigante
Keyword(s):  
Data Storage ◽  
Data Generation ◽  
Biologically Relevant ◽  
Sequencing Technologies ◽  
Long Term Storage ◽  
Oxford Nanopore ◽  
Long Read ◽  
Oxford Nanopore Technologies ◽  
Term Storage

Oxford Nanopore Technologies' (ONT's) MinION and PromethION long-read sequencing technologies are emerging as genuine alternatives to established Next-Generation Sequencing technologies. A combination of the highly redundant file format and a rapid increase in data generation have created a significant problem both for immediate data storage on MinION-capable laptops, and for long-term storage on lab data servers. We developed Picopore, a software suite offering three methods of compression. Picopore's lossless and deep lossless methods provide a 25% and 44% average reduction in size, respectively, without removing any data from the files. Picopore's raw method provides an 88% average reduction in size, while retaining biologically relevant data for the end-user. All methods have the capacity to run in real-time in parallel to a sequencing run, reducing demand for both immediate and long-term storage space.

scholarly journals Chasing perfection: validation and polishing strategies for telomere-to-telomere genome assemblies

2021 ◽  
Author(s):  
Arang Rhie ◽  
Ann Mc Cartney ◽  
Kishwar Shafin ◽  
Michael Alonge ◽  
Andrey Bzikadze ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Tandem Repeats ◽  
Hydatidiform Mole ◽  
Segmental Duplications ◽  
Sequencing Technologies ◽  
Oxford Nanopore ◽  
Human Genome Assembly ◽  
Long Read ◽  
Genome Assemblies ◽  
Oxford Nanopore Technologies

Abstract Advances in long-read sequencing technologies and genome assembly methods have enabled the recent completion of the first Telomere-to-Telomere (T2T) human genome assembly, which resolves complex segmental duplications and large tandem repeats, including centromeric satellite arrays in a complete hydatidiform mole (CHM13). Though derived from highly accurate sequencing, evaluation revealed that the initial T2T draft assembly had evidence of small errors and structural misassemblies. To correct these errors, we designed a novel repeat-aware polishing strategy that made accurate assembly corrections in large repeats without overcorrection, ultimately fixing 51% of the existing errors and improving the assembly QV to 73.9. By comparing our results to standard automated polishing tools, we outline common polishing errors and offer practical suggestions for genome projects with limited resources. We also show how sequencing biases in both PacBio HiFi and Oxford Nanopore Technologies reads cause signature assembly errors that can be corrected with a diverse panel of sequencing technologies

scholarly journals Construction of a chromosome-scale long-read reference genome assembly for potato

GigaScience ◽  
2020 ◽  
Vol 9 (9) ◽  
Author(s):  
Gina M Pham ◽  
John P Hamilton ◽  
Joshua C Wood ◽  
Joseph T Burke ◽  
Hainan Zhao ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Reference Genome ◽  
Agronomic Traits ◽  
Solanum Tuberosum L ◽  
Fold Increase ◽  
High Quality ◽  
Sequencing Technologies ◽  
Oxford Nanopore ◽  
Long Read ◽  
Oxford Nanopore Technologies

Abstract Background Worldwide, the cultivated potato, Solanum tuberosum L., is the No. 1 vegetable crop and a critical food security crop. The genome sequence of DM1–3 516 R44, a doubled monoploid clone of S. tuberosum Group Phureja, was published in 2011 using a whole-genome shotgun sequencing approach with short-read sequence data. Current advanced sequencing technologies now permit generation of near-complete, high-quality chromosome-scale genome assemblies at minimal cost. Findings Here, we present an updated version of the DM1–3 516 R44 genome sequence (v6.1) using Oxford Nanopore Technologies long reads coupled with proximity-by-ligation scaffolding (Hi-C), yielding a chromosome-scale assembly. The new (v6.1) assembly represents 741.6 Mb of sequence (87.8%) of the estimated 844 Mb genome, of which 741.5 Mb is non-gapped with 731.2 Mb anchored to the 12 chromosomes. Use of Oxford Nanopore Technologies full-length complementary DNA sequencing enabled annotation of 32,917 high-confidence protein-coding genes encoding 44,851 gene models that had a significantly improved representation of conserved orthologs compared with the previous annotation. The new assembly has improved contiguity with a 595-fold increase in N50 contig size, 99% reduction in the number of contigs, a 44-fold increase in N50 scaffold size, and an LTR Assembly Index score of 13.56, placing it in the category of reference genome quality. The improved assembly also permitted annotation of the centromeres via alignment to sequencing reads derived from CENH3 nucleosomes. Conclusions Access to advanced sequencing technologies and improved software permitted generation of a high-quality, long-read, chromosome-scale assembly and improved annotation dataset for the reference genotype of potato that will facilitate research aimed at improving agronomic traits and understanding genome evolution.

Long-term room temperature storage of DNA molecules

Biomics ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 552-563
Author(s):  
R.R. Garafutdinov ◽  
A.R. Sakhabutdinova ◽  
A.V. Chemeris
Keyword(s):  
Data Storage ◽  
Room Temperature ◽  
Biological Data ◽  
Dna Molecules ◽  
Freezing And Thawing ◽  
Long Term Storage ◽  
Wide Range ◽  
Frozen Solutions ◽  
Term Storage

The simplest and most common method of long-term storage of DNA samples at present is the storage of their frozen solutions, which, however, has a number of disadvantages, including the destruction of DNA molecules during freezing and thawing, as well as energy consumption and the likelihood of losing valuable samples in the event of possible accidents. In this regard, long-term storage of DNA samples at room temperature in a dried state is preferable, especially since an even greater increase in the number of stored DNA samples is planned due to the planned preservation of non-biological data in this molecule, which is recognized at the International Economic Forum 2019 among the 10 most important innovative technologies as “DNA Data Storage” of the near future of mankind. Such storage requires the exclusion of hydrolysis and oxidation of DNA molecules under the action of water and reactive oxygen species, which can be achieved by placing DNA in an inert anhydrous atmosphere, including in the presence of additional ingredients in the form of, for example, trehalose, imitating wildlife, since it is known that this simple disaccharide, capable of vitrification, protects a wide range of anhydrobiont organisms from adverse environmental conditions. Currently, there are a number of technologies that provide long-term storage of DNA at room temperature, including those available from commercial sources, but not all problems have yet been solved, which is reflected in this review article.

scholarly journals Comparison of the two up-to-date sequencing technologies for genome assembly: HiFi reads of Pacbio Sequel II system and ultralong reads of Oxford Nanopore

2020 ◽  
Author(s):  
Dandan Lang ◽  
Shilai Zhang ◽  
Pingping Ren ◽  
Fan Liang ◽  
Zongyi Sun ◽  
...  
Keyword(s):  
Gene Families ◽  
Single Chromosome ◽  
Small Indels ◽  
Base Level ◽  
Sequencing Technologies ◽  
Oxford Nanopore ◽  
Long Read ◽  
Single Rice ◽  
Genome Assemblies ◽  
Oxford Nanopore Technologies

AbstractThe availability of reference genomes has revolutionized the study of biology. Multiple competing technologies have been developed to improve the quality and robustness of genome assemblies during the last decade. The two widely-used long read sequencing providers – Pacbio (PB) and Oxford Nanopore Technologies (ONT) – have recently updated their platforms: PB enable high throughput HiFi reads with base-level resolution with >99% and ONT generated reads as long as 2 Mb. We applied the two up-to-date platforms to one single rice individual, and then compared the two assemblies to investigate the advantages and limitations of each. The results showed that ONT ultralong reads delivered higher contiguity producing a total of 18 contigs of which 10 were assembled into a single chromosome compared to that of 394 contigs and three chromosome-level contigs for the PB assembly. The ONT ultralong reads also prevented assembly errors caused by long repetitive regions for which we observed a total 44 genes of false redundancies and 10 genes of false losses in the PB assembly leading to over/under-estimations of the gene families in those long repetitive regions. We also noted that the PB HiFi reads generated assemblies with considerably less errors at the level of single nucleotide and small InDels than that of the ONT assembly which generated an average 1.06 errors per Kb assembly and finally engendered 1,475 incorrect gene annotations via altered or truncated protein predictions.

Long-term medical data storage: challenges with test results obtained by direct-to-consumer testing

2018 ◽  
Vol 42 (6) ◽  
pp. 235-242
Author(s):  
Matthias Orth ◽  
Frank Bühling ◽  
Georg Hoffmann
Keyword(s):  
Data Storage ◽  
High Volume ◽  
Gray Zone ◽  
Test Results ◽  
Direct To Consumer ◽  
Long Term Storage ◽  
Consumer Testing ◽  
Term Storage ◽  
Term Data

AbstractThe term “direct-to-consumer testing” (DTCT) describes all kinds of laboratory testing performed without the inclusion of a laboratory professional. It is thus performed in a gray zone between healthcare and consumers. The high volume of DTCT data as well as the ostensible feasibility of long-term data storage challenge medical professionals and consumers. No standards have been developed so far for the long-term storage of DTCT data. Unlike tests used in traditional laboratory medicine, many DTCT tests lack medical usefulness. This article describes the current concepts of DTCT and gives recommendations for the long-term data storage of DTCT data depending on the purpose of DTCT, the volume of data obtained and the possible medical implications of the test results.

scholarly journals Benchmarking of long-read correction methods

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Juliane C Dohm ◽  
Philipp Peters ◽  
Nancy Stralis-Pavese ◽  
Heinz Himmelbauer
Keyword(s):  
Error Rate ◽  
Total Error ◽  
Error Rates ◽  
High Rate ◽  
Sequencing Technologies ◽  
Third Generation Sequencing ◽  
Oxford Nanopore ◽  
Long Read ◽  
Oxford Nanopore Technologies ◽  
Generation Sequencing

Abstract Third-generation sequencing technologies provided by Pacific Biosciences and Oxford Nanopore Technologies generate read lengths in the scale of kilobasepairs. However, these reads display high error rates, and correction steps are necessary to realize their great potential in genomics and transcriptomics. Here, we compare properties of PacBio and Nanopore data and assess correction methods by Canu, MARVEL and proovread in various combinations. We found total error rates of around 13% in the raw datasets. PacBio reads showed a high rate of insertions (around 8%) whereas Nanopore reads showed similar rates for substitutions, insertions and deletions of around 4% each. In data from both technologies the errors were uniformly distributed along reads apart from noisy 5′ ends, and homopolymers appeared among the most over-represented kmers relative to a reference. Consensus correction using read overlaps reduced error rates to about 1% when using Canu or MARVEL after patching. The lowest error rate in Nanopore data (0.45%) was achieved by applying proovread on MARVEL-patched data including Illumina short-reads, and the lowest error rate in PacBio data (0.42%) was the result of Canu correction with minimap2 alignment after patching. Our study provides valuable insights and benchmarks regarding long-read data and correction methods.

scholarly journals SLR: a scaffolding algorithm based on long reads and contig classification

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Junwei Luo ◽  
Mengna Lyu ◽  
Ranran Chen ◽  
Xiaohong Zhang ◽  
Huimin Luo ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Pacific Biosciences ◽  
Sequencing Technologies ◽  
Third Generation Sequencing ◽  
Long Reads ◽  
Oxford Nanopore ◽  
New Strategy ◽  
Long Read ◽  
Oxford Nanopore Technologies ◽  
Unique Contigs

Abstract Background Scaffolding is an important step in genome assembly that orders and orients the contigs produced by assemblers. However, repetitive regions in contigs usually prevent scaffolding from producing accurate results. How to solve the problem of repetitive regions has received a great deal of attention. In the past few years, long reads sequenced by third-generation sequencing technologies (Pacific Biosciences and Oxford Nanopore) have been demonstrated to be useful for sequencing repetitive regions in genomes. Although some stand-alone scaffolding algorithms based on long reads have been presented, scaffolding still requires a new strategy to take full advantage of the characteristics of long reads. Results Here, we present a new scaffolding algorithm based on long reads and contig classification (SLR). Through the alignment information of long reads and contigs, SLR classifies the contigs into unique contigs and ambiguous contigs for addressing the problem of repetitive regions. Next, SLR uses only unique contigs to produce draft scaffolds. Then, SLR inserts the ambiguous contigs into the draft scaffolds and produces the final scaffolds. We compare SLR to three popular scaffolding tools by using long read datasets sequenced with Pacific Biosciences and Oxford Nanopore technologies. The experimental results show that SLR can produce better results in terms of accuracy and completeness. The open-source code of SLR is available at https://github.com/luojunwei/SLR. Conclusion In this paper, we describes SLR, which is designed to scaffold contigs using long reads. We conclude that SLR can improve the completeness of genome assembly.

scholarly journals Chasing perfection: validation and polishing strategies for telomere-to-telomere genome assemblies

2021 ◽  
Author(s):  
Ann M Mc Cartney ◽  
Kishwar Shafin ◽  
Michael Alonge ◽  
Andrey V Bzikadze ◽  
Giulio Formenti ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Tandem Repeats ◽  
Hydatidiform Mole ◽  
Segmental Duplications ◽  
Sequencing Technologies ◽  
Oxford Nanopore ◽  
Human Genome Assembly ◽  
Long Read ◽  
Genome Assemblies ◽  
Oxford Nanopore Technologies

Advances in long-read sequencing technologies and genome assembly methods have enabled the recent completion of the first Telomere-to-Telomere (T2T) human genome assembly, which resolves complex segmental duplications and large tandem repeats, including centromeric satellite arrays in a complete hydatidiform mole (CHM13). Though derived from highly accurate sequencing, evaluation revealed that the initial T2T draft assembly had evidence of small errors and structural misassemblies. To correct these errors, we designed a novel repeat-aware polishing strategy that made accurate assembly corrections in large repeats without overcorrection, ultimately fixing 51% of the existing errors and improving the assembly QV to 73.9. By comparing our results to standard automated polishing tools, we outline common polishing errors and offer practical suggestions for genome projects with limited resources. We also show how sequencing biases in both PacBio HiFi and Oxford Nanopore Technologies reads cause signature assembly errors that can be corrected with a diverse panel of sequencing technologies.

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