scholarly journals Complete representation of a tapeworm genome reveals chromosomes capped by centromeres, necessitating a dual role in segregation and protection

BMC Biology ◽  
2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Peter D. Olson ◽  
Alan Tracey ◽  
Andrew Baillie ◽  
Katherine James ◽  
Stephen R. Doyle ◽  
...  
Keyword(s):  
Complete Genome ◽  
Gene Prediction ◽  
Low Complexity ◽  
Complex Species ◽  
Complete Representation ◽  
Spliced Leader ◽  
Long Read ◽  
Reference Quality ◽  
Species Specific ◽  
Genome Representation

Abstract Background Chromosome-level assemblies are indispensable for accurate gene prediction, synteny assessment, and understanding higher-order genome architecture. Reference and draft genomes of key helminth species have been published, but little is yet known about the biology of their chromosomes. Here, we present the complete genome of the tapeworm Hymenolepis microstoma, providing a reference quality, end-to-end assembly that represents the first fully assembled genome of a spiralian/lophotrochozoan, revealing new insights into chromosome evolution. Results Long-read sequencing and optical mapping data were added to previous short-read data enabling complete re-assembly into six chromosomes, consistent with karyology. Small genome size (169 Mb) and lack of haploid variation (1 SNP/3.2 Mb) contributed to exceptionally high contiguity with only 85 gaps remaining in regions of low complexity sequence. Resolution of repeat regions reveals novel gene expansions, micro-exon genes, and spliced leader trans-splicing, and illuminates the landscape of transposable elements, explaining observed length differences in sister chromatids. Syntenic comparison with other parasitic flatworms shows conserved ancestral linkage groups indicating that the H. microstoma karyotype evolved through fusion events. Strikingly, the assembly reveals that the chromosomes terminate in centromeric arrays, indicating that these motifs play a role not only in segregation, but also in protecting the linear integrity and full lengths of chromosomes. Conclusions Despite strong conservation of canonical telomeres, our results show that they can be substituted by more complex, species-specific sequences, as represented by centromeres. The assembly provides a robust platform for investigations that require complete genome representation.

scholarly journals Complete representation of a tapeworm genome reveals chromosomes capped by centromeres, necessitating a dual role in segregation and protection

2020 ◽  
Author(s):  
Peter D. Olson ◽  
Alan Tracey ◽  
Andrew Baillie ◽  
Katherine James ◽  
Stephen R. Doyle ◽  
...  
Keyword(s):  
Complete Genome ◽  
Gene Prediction ◽  
Low Complexity ◽  
Complex Species ◽  
Complete Representation ◽  
Spliced Leader ◽  
Long Read ◽  
Reference Quality ◽  
Species Specific ◽  
Genome Representation

AbstractBackgroundChromosome-level assemblies are indispensable for accurate gene prediction, synteny assessment and understanding higher-order genome architecture. Reference and draft genomes of key helminth species have been published but little is yet known about the biology of their chromosomes. Here we present the complete genome of the tapeworm Hymenolepis microstoma, providing a reference-quality, end-to-end assembly that represents the first fully assembled genome of a spiralian/lophotrochozoan, revealing new insights into chromosome evolution.ResultsLong-read sequencing and optical mapping data were added to previous short-read data enabling complete re-assembly into six chromosomes, consistent with karyology. Small genome size (169 Mb) and lack of haploid variation (1 SNP/3.2 Mb) contributed to exceptionally high contiguity with only 85 gaps remaining in regions of low complexity sequence. Resolution of repeat regions reveals novel gene expansions, micro-exon genes, and spliced leader transsplicing, and illuminates the landscape of transposable elements, explaining observed length differences in sister chromatids. Syntenic comparison with other parasitic flatworms shows conserved ancestral linkage groups indicating that the H. microstoma karyotype evolved through fusion events. Strikingly, the assembly reveals that the chromosomes terminate in centromeric arrays, indicating that these motifs play a role not only in segregation, but also in protecting the linear integrity and full lengths of chromosomes.ConclusionsDespite strong conservation of canonical telomeres, our results show that they can be substituted by more complex, species-specific sequences, as represented by centromeres. The assembly provides a robust platform for investigations that require complete genome representation.

scholarly journals Complete Genome Sequence of Multidrug-Resistant Strain Nocardia wallacei FMUON74, Isolated from a Sputum Culture

2020 ◽  
Vol 9 (47) ◽  
Author(s):  
Masahiro Toyokawa ◽  
Makoto Taniguchi ◽  
Kazuma Uesaka ◽  
Keiko Nishimura
Keyword(s):  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Resistant Strain ◽  
Complete Genome ◽  
Hybrid Approach ◽  
Multidrug Resistant ◽  
Content Type ◽  
Short Read Sequencing ◽  
Long Read ◽  
Multidrug Resistant Strain

ABSTRACT Nocardia wallacei is one of the members of the N. transvalensis complex which possess a highly unique susceptibility pattern. Here, we describe the closed complete genome sequence of the multidrug-resistant strain N. wallacei FMUON74, which was obtained using a hybrid approach combining Nanopore long-read sequencing and Illumina and DNBseq short-read sequencing.

scholarly journals Chromosome-Scale Assembly of the Complete Genome Sequence of Porcisia hertigi, Isolate C119, Strain LV43

2021 ◽  
Vol 10 (41) ◽  
Author(s):  
Hatim Almutairi ◽  
Michael D. Urbaniak ◽  
Michelle D. Bates ◽  
Waleed S. Al-Salem ◽  
Rod J. Dillon ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Content Type ◽  
Long Read ◽  
Central Panama

Porcisia hertigi is a parasitic kinetoplastid first isolated from porcupines ( Coendou rothschildi ) in central Panama in 1965. We present the complete genome sequence of P. hertigi , isolate C119, strain LV43, sequenced using combined short- and long-read technologies. This complete genome sequence will contribute to our knowledge of the parasitic genus Porcisia .

scholarly journals Complete Genome Sequence of SMBL-WEM22, a Halotolerant Strain of Kosakonia cowanii Isolated from Hong Kong Seawater

2021 ◽  
Vol 10 (41) ◽  
Author(s):  
W. E. Moore ◽  
G. K. K. Lai ◽  
S. D. J. Griffin ◽  
F. C. C. Leung
Keyword(s):  
Hong Kong ◽  
Dna Sequences ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Gc Content ◽  
Hybrid Assembly ◽  
Gram Negative ◽  
Content Type ◽  
Facultative Anaerobic ◽  
Long Read

Kosakonia cowanii is a Gram-negative, motile, facultative anaerobic enterobacterium that is found in soil, water, and sewage. K. cowanii SMBL-WEM22 is a halotolerant strain that was isolated from seawater in Hong Kong. The complete genome of SMBL-WEM22 (5,037,617 bp, with a GC content of 55.02%) was determined by hybrid assembly of short- and long-read DNA sequences.

scholarly journals Complete Genome Sequences of 12 Quinolone-Resistant Escherichia coli Strains Containing qnrS1 Based on Hybrid Assemblies

2021 ◽  
Vol 10 (4) ◽  
Author(s):  
Håkon Kaspersen ◽  
Thomas H. A. Haverkamp ◽  
Hanna Karin Ilag ◽  
Øivind Øines ◽  
Camilla Sekse ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Complete Genome ◽  
Flow Cell ◽  
Hybrid Assembly ◽  
Genome Sequences ◽  
Content Type ◽  
Short Reads ◽  
Long Reads ◽  
Long Read ◽  
Hybrid Assemblies

ABSTRACT In total, 12 quinolone-resistant Escherichia coli (QREC) strains containing qnrS1 were submitted to long-read sequencing using a FLO-MIN106 flow cell on a MinION device. The long reads were assembled with short reads (Illumina) and analyzed using the MOB-suite pipeline. Six of these QREC genome sequences were closed after hybrid assembly.

scholarly journals Complete Genome Resequencing of Thermus thermophilus Strain TMY by Hybrid Assembly of Long- and Short-Read Sequencing Technologies

2021 ◽  
Vol 10 (46) ◽  
Author(s):  
Kentaro Miyazaki ◽  
Natsuko Tokito
Keyword(s):  
Complete Genome ◽  
Thermus Thermophilus ◽  
Genomic Analysis ◽  
Comparative Genomic ◽  
Hybrid Assembly ◽  
Genome Resequencing ◽  
Short Read ◽  
Content Type ◽  
Sequencing Technologies ◽  
Long Read

Complete genome resequencing was conducted for Thermus thermophilus strain TMY by hybrid assembly of Oxford Nanopore Technologies long-read and MGI short-read data. Errors in the previously reported genome sequence determined by PacBio technology alone were corrected, allowing for high-quality comparative genomic analysis of closely related T. thermophilus genomes.

scholarly journals Oxford Nanopore Sequencing, Hybrid Error Correction, and de novo Assembly of a Eukaryotic Genome

2015 ◽  
Author(s):  
Sara Goodwin ◽  
James Gurtowski ◽  
Scott Ethe-Sayers ◽  
Panchajanya Deshpande ◽  
Michael Schatz ◽  
...  
Keyword(s):  
Error Correction ◽  
De Novo Assembly ◽  
De Novo ◽  
Correction Algorithm ◽  
Membrane Pore ◽  
Complete Representation ◽  
Oxford Nanopore ◽  
Long Read ◽  
Error Correction Algorithm ◽  
Sequencing Instrument

Monitoring the progress of DNA molecules through a membrane pore has been postulated as a method for sequencing DNA for several decades. Recently, a nanopore-based sequencing instrument, the Oxford Nanopore MinION, has become available that we used for sequencing the S. cerevisiae genome. To make use of these data, we developed a novel open-source hybrid error correction algorithm Nanocorr (https://github.com/jgurtowski/nanocorr) specifically for Oxford Nanopore reads, as existing packages were incapable of assembling the long read lengths (5-50kbp) at such high error rate (between ~5 and 40% error). With this new method we were able to perform a hybrid error correction of the nanopore reads using complementary MiSeq data and produce a de novo assembly that is highly contiguous and accurate: the contig N50 length is more than ten-times greater than an Illumina-only assembly (678kb versus 59.9kbp), and has greater than 99.88% consensus identity when compared to the reference. Furthermore, the assembly with the long nanopore reads presents a much more complete representation of the features of the genome and correctly assembles gene cassettes, rRNAs, transposable elements, and other genomic features that were almost entirely absent in the Illumina-only assembly.

scholarly journals HiC-Hiker: a probabilistic model to determine contig orientation in chromosome-length scaffolds with Hi-C

2020 ◽  
Vol 36 (13) ◽  
pp. 3966-3974
Author(s):  
Ryo Nakabayashi ◽  
Shinichi Morishita
Keyword(s):  
Viterbi Algorithm ◽  
De Novo ◽  
Gene Prediction ◽  
Effective Means ◽  
Cost Effective ◽  
Synteny Block ◽  
Chromosome Length ◽  
Model Organisms ◽  
Contact Frequency ◽  
Reference Quality

Abstract Motivation De novo assembly of reference-quality genomes used to require enormously laborious tasks. In particular, it is extremely time-consuming to build genome markers for ordering assembled contigs along chromosomes; thus, they are only available for well-established model organisms. To resolve this issue, recent studies demonstrated that Hi-C could be a powerful and cost-effective means to output chromosome-length scaffolds for non-model species with no genome marker resources, because the Hi-C contact frequency between a pair of two loci can be a good estimator of their genomic distance, even if there is a large gap between them. Indeed, state-of-the-art methods such as 3D-DNA are now widely used for locating contigs in chromosomes. However, it remains challenging to reduce errors in contig orientation because shorter contigs have fewer contacts with their neighboring contigs. These orientation errors lower the accuracy of gene prediction, read alignment, and synteny block estimation in comparative genomics. Results To reduce these contig orientation errors, we propose a new algorithm, named HiC-Hiker, which has a firm grounding in probabilistic theory, rigorously models Hi-C contacts across contigs, and effectively infers the most probable orientations via the Viterbi algorithm. We compared HiC-Hiker and 3D-DNA using human and worm genome contigs generated from short reads, evaluated their performances, and observed a remarkable reduction in the contig orientation error rate from 4.3% (3D-DNA) to 1.7% (HiC-Hiker). Our algorithm can consider long-range information between distal contigs and precisely estimates Hi-C read contact probabilities among contigs, which may also be useful for determining the ordering of contigs. Availability and implementation HiC-Hiker is freely available at: https://github.com/ryought/hic_hiker.

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

2019 ◽  
Vol 8 (34) ◽  
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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