Pangenome-based genome inference

AbstractTypical analysis workflows map reads to a reference genome in order to detect genetic variants. Generating such alignments introduces references biases, in particular against insertion alleles absent in the reference and comes with substantial computational burden. In contrast, recent k-mer-based genotyping methods are fast, but struggle in repetitive or duplicated regions of the genome. We propose a novel algorithm, called PanGenie, that leverages a pangenome reference built from haplotype-resolved genome assemblies in conjunction with k-mer count information from raw, short-read sequencing data to genotype a wide spectrum of genetic variation. The given haplotypes enable our method to take advantage of linkage information to aid genotyping in regions poorly covered by unique k-mers and provides access to regions otherwise inaccessible by short reads. Compared to classic mapping-based approaches, our approach is more than 4× faster at 30× coverage and at the same time, reached significantly better genotype concordances for almost all variant types and coverages tested. Improvements are especially pronounced for large insertions (> 50bp), where we are able to genotype > 99.9% of all tested variants with over 90% accuracy at 30× short-read coverage, where the best competing tools either typed less than 60% of variants or reached accuracies below 70%. PanGenie now enables the inclusion of this commonly neglected variant type in downstream analyses.

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DACCOR - Detection, charACterization, and reconstruction of Repetitive regions in bacterial genomes

10.7287/peerj.preprints.3480v1 ◽

2017 ◽

Author(s):

Alexander Seitz ◽

Friederike Hanssen ◽

Kay Nieselt

Keyword(s):

Base Pair ◽

Repetitive Sequence ◽

Reference Genome ◽

De Novo ◽

Treponema Pallidum ◽

Sequencing Data ◽

Bacterial Genomes ◽

Short Read ◽

Short Reads ◽

Short Read Sequencing

The reconstruction of genomes using mapping based approaches with short reads experiences difficulties when resolving repetitive regions. These repetitive regions in genomes result in low mapping qualities of the respective reads, which in turn lead to many unresolved bases of the genotypers. Currently, the reconstruction of these regions is often based on modified references in which the repetitive regions are masked. However, for many references such masked genomes are not available or are based on repetitive regions of other genomes. Our idea is to identify repetitive regions in the reference genome de novo. These regions can then be used to reconstruct them separately using short read sequencing data. Afterwards the reconstructed repetitive sequence can be inserted into the reconstructed genome. We present the program DACCOR, which performs these steps automatically. Our results show an increased base pair resolution of the repetitive regions in the reconstruction of Treponema pallidum samples, resulting in fewer unresolved bases.

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DACCOR–Detection, characterization, and reconstruction of repetitive regions in bacterial genomes

PeerJ ◽

10.7717/peerj.4742 ◽

2018 ◽

Vol 6 ◽

pp. e4742 ◽

Cited By ~ 1

Author(s):

Alexander Seitz ◽

Friederike Hanssen ◽

Kay Nieselt

Keyword(s):

Base Pair ◽

Repetitive Sequence ◽

Reference Genome ◽

De Novo ◽

Treponema Pallidum ◽

Sequencing Data ◽

Bacterial Genomes ◽

Short Read ◽

Short Reads ◽

Short Read Sequencing

The reconstruction of genomes using mapping-based approaches with short reads experiences difficulties when resolving repetitive regions. These repetitive regions in genomes result in low mapping qualities of the respective reads, which in turn lead to many unresolved bases. Currently, the reconstruction of these regions is often based on modified references in which the repetitive regions are masked. However, for many references, such masked genomes are not available or are based on repetitive regions of other genomes. Our idea is to identify repetitive regions in the reference genome de novo. These regions can then be used to reconstruct them separately using short read sequencing data. Afterward, the reconstructed repetitive sequence can be inserted into the reconstructed genome. We present the program detection, characterization, and reconstruction of repetitive regions, which performs these steps automatically. Our results show an increased base pair resolution of the repetitive regions in the reconstruction of Treponema pallidum samples, resulting in fewer unresolved bases.

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DACCOR - Detection, charACterization, and reconstruction of Repetitive regions in bacterial genomes

10.7287/peerj.preprints.3480 ◽

2017 ◽

Author(s):

Alexander Seitz ◽

Friederike Hanssen ◽

Kay Nieselt

Keyword(s):

Base Pair ◽

Repetitive Sequence ◽

Reference Genome ◽

De Novo ◽

Treponema Pallidum ◽

Sequencing Data ◽

Bacterial Genomes ◽

Short Read ◽

Short Reads ◽

Short Read Sequencing

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REscan: inferring repeat expansions and structural variation in paired-end short read sequencing data

Bioinformatics ◽

10.1093/bioinformatics/btaa753 ◽

2020 ◽

Author(s):

Russell Lewis McLaughlin

Keyword(s):

Structural Variation ◽

Sequence Data ◽

Neurological Diseases ◽

Repeat Expansion ◽

Sequencing Data ◽

Short Read ◽

Short Read Sequencing ◽

Repeat Expansions ◽

Paired End Sequencing

Abstract Motivation Repeat expansions are an important class of genetic variation in neurological diseases. However, the identification of novel repeat expansions using conventional sequencing methods is a challenge due to their typical lengths relative to short sequence reads and difficulty in producing accurate and unique alignments for repetitive sequence. However, this latter property can be harnessed in paired-end sequencing data to infer the possible locations of repeat expansions and other structural variation. Results This article presents REscan, a command-line utility that infers repeat expansion loci from paired-end short read sequencing data by reporting the proportion of reads orientated towards a locus that do not have an adequately mapped mate. A high REscan statistic relative to a population of data suggests a repeat expansion locus for experimental follow-up. This approach is validated using genome sequence data for 259 cases of amyotrophic lateral sclerosis, of which 24 are positive for a large repeat expansion in C9orf72, showing that REscan statistics readily discriminate repeat expansion carriers from non-carriers. Availabilityand implementation C source code at https://github.com/rlmcl/rescan (GNU General Public Licence v3).

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High resolution copy number inference in cancer using short-molecule nanopore sequencing

10.1101/2020.12.28.424602 ◽

2020 ◽

Author(s):

Timour Baslan ◽

Sam Kovaka ◽

Fritz J. Sedlazeck ◽

Yanming Zhang ◽

Robert Wappel ◽

...

Keyword(s):

Copy Number ◽

Cost Effective ◽

Chromosome Analysis ◽

Ease Of Use ◽

Precision Oncology ◽

Nanopore Sequencing ◽

Dna Molecules ◽

Sequencing Data ◽

Short Read ◽

Short Read Sequencing

ABSTRACTGenome copy number is an important source of genetic variation in health and disease. In cancer, clinically actionable Copy Number Alterations (CNAs) can be inferred from short-read sequencing data, enabling genomics-based precision oncology. Emerging Nanopore sequencing technologies offer the potential for broader clinical utility, for example in smaller hospitals, due to lower instrument cost, higher portability, and ease of use. Nonetheless, Nanopore sequencing devices are limited in terms of the number of retrievable sequencing reads/molecules compared to short-read sequencing platforms. This represents a challenge for applications that require high read counts such as CNA inference. To address this limitation, we targeted the sequencing of short-length DNA molecules loaded at optimized concentration in an effort to increase sequence read/molecule yield from a single nanopore run. We show that sequencing short DNA molecules reproducibly returns high read counts and allows high quality CNA inference. We demonstrate the clinical relevance of this approach by accurately inferring CNAs in acute myeloid leukemia samples. The data shows that, compared to traditional approaches such as chromosome analysis/cytogenetics, short molecule nanopore sequencing returns more sensitive, accurate copy number information in a cost effective and expeditious manner, including for multiplex samples. Our results provide a framework for the sequencing of relatively short DNA molecules on nanopore devices with applications in research and medicine, that include but are not limited to, CNAs.

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Rapid Mycobacterium tuberculosis spoligotyping from uncorrected long reads using Galru

10.1101/2020.05.31.126490 ◽

2020 ◽

Author(s):

Andrew J. Page ◽

Nabil-Fareed Alikhan ◽

Michael Strinden ◽

Thanh Le Viet ◽

Timofey Skvortsov

Keyword(s):

Mycobacterium Tuberculosis ◽

State Of The Art ◽

Sequence Data ◽

Human Pathogen ◽

Sequencing Data ◽

Short Read ◽

Short Read Sequencing ◽

Long Reads ◽

Long Read

AbstractSpoligotyping of Mycobacterium tuberculosis provides a subspecies classification of this major human pathogen. Spoligotypes can be predicted from short read genome sequencing data; however, no methods exist for long read sequence data such as from Nanopore or PacBio. We present a novel software package Galru, which can rapidly detect the spoligotype of a Mycobacterium tuberculosis sample from as little as a single uncorrected long read. It allows for near real-time spoligotyping from long read data as it is being sequenced, giving rapid sample typing. We compare it to the existing state of the art software and find it performs identically to the results obtained from short read sequencing data. Galru is freely available from https://github.com/quadram-institute-bioscience/galru under the GPLv3 open source licence.

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A Transposon Story: From TE Content to TE Dynamic Invasion of Drosophila Genomes Using the Single-Molecule Sequencing Technology from Oxford Nanopore

Cells ◽

10.3390/cells9081776 ◽

2020 ◽

Vol 9 (8) ◽

pp. 1776

Author(s):

Mourdas Mohamed ◽

Nguyet Thi-Minh Dang ◽

Yuki Ogyama ◽

Nelly Burlet ◽

Bruno Mugat ◽

...

Keyword(s):

Single Molecule ◽

Wild Type ◽

Sequencing Data ◽

Short Read ◽

Short Read Sequencing ◽

Sequencing Technologies ◽

Oxford Nanopore ◽

In The Wild ◽

Successive Generations ◽

Type Strains

Transposable elements (TEs) are the main components of genomes. However, due to their repetitive nature, they are very difficult to study using data obtained with short-read sequencing technologies. Here, we describe an efficient pipeline to accurately recover TE insertion (TEI) sites and sequences from long reads obtained by Oxford Nanopore Technology (ONT) sequencing. With this pipeline, we could precisely describe the landscapes of the most recent TEIs in wild-type strains of Drosophila melanogaster and Drosophila simulans. Their comparison suggests that this subset of TE sequences is more similar than previously thought in these two species. The chromosome assemblies obtained using this pipeline also allowed recovering piRNA cluster sequences, which was impossible using short-read sequencing. Finally, we used our pipeline to analyze ONT sequencing data from a D. melanogaster unstable line in which LTR transposition was derepressed for 73 successive generations. We could rely on single reads to identify new insertions with intact target site duplications. Moreover, the detailed analysis of TEIs in the wild-type strains and the unstable line did not support the trap model claiming that piRNA clusters are hotspots of TE insertions.

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Complete Genome Sequence of Rubrobacter xylanophilus Strain AA3-22, Isolated from Arima Onsen in Japan

Microbiology Resource Announcements ◽

10.1128/mra.00818-19 ◽

2019 ◽

Vol 8 (34) ◽

Cited By ~ 1

Author(s):

Natsuki Tomariguchi ◽

Kentaro Miyazaki

Keyword(s):

Genome Sequence ◽

Complete Genome Sequence ◽

Complete Genome ◽

Hot Spring ◽

Sequencing Data ◽

Short Read ◽

Content Type ◽

Short Read Sequencing ◽

Oxford Nanopore ◽

Long Read

Rubrobacter xylanophilus strain AA3-22, belonging to the phylum Actinobacteria, was isolated from nonvolcanic Arima Onsen (hot spring) in Japan. Here, we report the complete genome sequence of this organism, which was obtained by combining Oxford Nanopore long-read and Illumina short-read sequencing data.

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CNV_IFTV: an isolation forest and total variation-based detection of CNVs from short-read sequencing data

IEEE/ACM Transactions on Computational Biology and Bioinformatics ◽

10.1109/tcbb.2019.2920889 ◽

2019 ◽

pp. 1-1 ◽

Cited By ~ 5

Author(s):

Xiguo Yuan ◽

Jiaao Yu ◽

Jianing Xi ◽

Liying Yang ◽

Junliang Shang ◽

...

Keyword(s):

Total Variation ◽

Sequencing Data ◽

Short Read ◽

Short Read Sequencing ◽

Isolation Forest

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Fast and accurate HLA typing from short-read next-generation sequence data with xHLA

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1707945114 ◽

2017 ◽

Vol 114 (30) ◽

pp. 8059-8064 ◽

Cited By ~ 54

Author(s):

Chao Xie ◽

Zhen Xuan Yeo ◽

Marie Wong ◽

Jason Piper ◽

Tao Long ◽

...

Keyword(s):

Sequence Data ◽

Sequence Similarity ◽

Amino Acid Level ◽

Hla Typing ◽

Sequencing Data ◽

Desktop Computer ◽

Short Read ◽

Short Read Sequencing ◽

Hla Genes ◽

Human Chromosome 6

The HLA gene complex on human chromosome 6 is one of the most polymorphic regions in the human genome and contributes in large part to the diversity of the immune system. Accurate typing of HLA genes with short-read sequencing data has historically been difficult due to the sequence similarity between the polymorphic alleles. Here, we introduce an algorithm, xHLA, that iteratively refines the mapping results at the amino acid level to achieve 99–100% four-digit typing accuracy for both class I and II HLA genes, taking only∼3 min to process a 30× whole-genome BAM file on a desktop computer.

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