scholarly journals Construction of a new chromosome-scale, long-read reference genome assembly of the Syrian hamster, Mesocricetus auratus

2021 ◽  
Author(s):  
R. Alan Harris ◽  
Muthuswamy Raveendran ◽  
Dustin T Lyfoung ◽  
Fritz J Sedlazeck ◽  
Medhat Mahmoud ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Syrian Hamster ◽  
Reference Genome ◽  
Sequence Data ◽  
Mesocricetus Auratus ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Sequencing Technologies ◽  
Long Read ◽  
Short Read Sequence

Background The Syrian hamster (Mesocricetus auratus) has been suggested as a useful mammalian model for a variety of diseases and infections, including infection with respiratory viruses such as SARS-CoV-2. The MesAur1.0 genome assembly was published in 2013 using whole-genome shotgun sequencing with short-read sequence data. Current more advanced sequencing technologies and assembly methods now permit the generation of near-complete genome assemblies with higher quality and higher continuity. Findings Here, we report an improved assembly of the M. auratus genome (BCM_Maur_2.0) using Oxford Nanopore Technologies long-read sequencing to produce a chromosome-scale assembly. The total length of the new assembly is 2.46 Gbp, similar to the 2.50 Gbp length of a previous assembly of this genome, MesAur1.0. BCM_Maur_2.0 exhibits significantly improved continuity with a scaffold N50 that is 6.7 times greater than MesAur1.0. Furthermore, 21,616 protein coding genes and 10,459 noncoding genes were annotated in BCM_Maur_2.0 compared to 20,495 protein coding genes and 4,168 noncoding genes in MesAur1.0. This new assembly also improves the unresolved regions as measured by nucleotide ambiguities, where approximately 17.11% of bases in MesAur1.0 were unresolved compared to BCM_Maur_2.0 in which the number of unresolved bases is reduced to 3.00%. Conclusions Access to a more complete reference genome with improved accuracy and continuity will facilitate more detailed, comprehensive, and meaningful research results for a wide variety of future studies using Syrian hamsters as models.

scholarly journals Chromosome-level assembly of Drosophila bifasciata reveals important karyotypic transition of the X chromosome

2019 ◽  
Author(s):  
Ryan Bracewell ◽  
Anita Tran ◽  
Kamalakar Chatla ◽  
Doris Bachtrog
Keyword(s):  
X Chromosome ◽  
Genome Assembly ◽  
De Novo ◽  
Pericentromeric Region ◽  
Species Group ◽  
Chromosome 15 ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Long Read ◽  
Chromosome Level

ABSTRACTThe Drosophila obscura species group is one of the most studied clades of Drosophila and harbors multiple distinct karyotypes. Here we present a de novo genome assembly and annotation of D. bifasciata, a species which represents an important subgroup for which no high-quality chromosome-level genome assembly currently exists. We combined long-read sequencing (Nanopore) and Hi-C scaffolding to achieve a highly contiguous genome assembly approximately 193Mb in size, with repetitive elements constituting 30.1% of the total length. Drosophila bifasciata harbors four large metacentric chromosomes and the small dot, and our assembly contains each chromosome in a single scaffold, including the highly repetitive pericentromere, which were largely composed of Jockey and Gypsy transposable elements. We annotated a total of 12,821 protein-coding genes and comparisons of synteny with D. athabasca orthologs show that the large metacentric pericentromeric regions of multiple chromosomes are conserved between these species. Importantly, Muller A (X chromosome) was found to be metacentric in D. bifasciata and the pericentromeric region appears homologous to the pericentromeric region of the fused Muller A-AD (XL and XR) of pseudoobscura/affinis subgroup species. Our finding suggests a metacentric ancestral X fused to a telocentric Muller D and created the large neo-X (Muller A-AD) chromosome ∼15 MYA. We also confirm the fusion of Muller C and D in D. bifasciata and show that it likely involved a centromere-centromere fusion.

scholarly journals A Chromosome-Scale Genome Assembly Resource for Myriosclerotinia sulcatula Infecting Sedge Grass (Carex sp.)

2020 ◽  
Vol 33 (7) ◽  
pp. 880-883
Author(s):  
Stefan Kusch ◽  
Heba M. M. Ibrahim ◽  
Catherine Zanchetta ◽  
Celine Lopez-Roques ◽  
Cecile Donnadieu ◽  
...  
Keyword(s):  
Host Range ◽  
Sclerotinia Sclerotiorum ◽  
Genome Assembly ◽  
Plant Pathogens ◽  
Reference Genome ◽  
Close Relative ◽  
High Quality ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Reference Genome Assembly

The fungus Myriosclerotinia sulcatula is a close relative of the notorious polyphagous plant pathogens Botrytis cinerea and Sclerotinia sclerotiorum but exhibits a host range restricted to plants from the Carex genus (Cyperaceae family). To date, there are no genomic resources available for fungi in the Myriosclerotinia genus. Here, we present a chromosome-scale reference genome assembly for M. sulcatula. The assembly contains 24 contigs with a total length of 43.53 Mbp, with scaffold N50 of 2,649.7 kbp and N90 of 1,133.1 kbp. BRAKER-predicted gene models were manually curated using WebApollo, resulting in 11,275 protein-coding genes that we functionally annotated. We provide a high-quality reference genome assembly and annotation for M. sulcatula as a resource for studying evolution and pathogenicity in fungi from the Sclerotiniaceae family.

scholarly journals Chromosome-Level Assembly of Drosophila bifasciata Reveals Important Karyotypic Transition of the X Chromosome

2020 ◽  
Vol 10 (3) ◽  
pp. 891-897 ◽  
Author(s):  
Ryan Bracewell ◽  
Anita Tran ◽  
Kamalakar Chatla ◽  
Doris Bachtrog
Keyword(s):  
X Chromosome ◽  
Genome Assembly ◽  
De Novo ◽  
Pericentromeric Region ◽  
Species Group ◽  
Chromosome 15 ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Long Read ◽  
Chromosome Level

The Drosophila obscura species group is one of the most studied clades of Drosophila and harbors multiple distinct karyotypes. Here we present a de novo genome assembly and annotation of D. bifasciata, a species which represents an important subgroup for which no high-quality chromosome-level genome assembly currently exists. We combined long-read sequencing (Nanopore) and Hi-C scaffolding to achieve a highly contiguous genome assembly approximately 193 Mb in size, with repetitive elements constituting 30.1% of the total length. Drosophila bifasciata harbors four large metacentric chromosomes and the small dot, and our assembly contains each chromosome in a single scaffold, including the highly repetitive pericentromeres, which were largely composed of Jockey and Gypsy transposable elements. We annotated a total of 12,821 protein-coding genes and comparisons of synteny with D. athabasca orthologs show that the large metacentric pericentromeric regions of multiple chromosomes are conserved between these species. Importantly, Muller A (X chromosome) was found to be metacentric in D. bifasciata and the pericentromeric region appears homologous to the pericentromeric region of the fused Muller A-AD (XL and XR) of pseudoobscura/affinis subgroup species. Our finding suggests a metacentric ancestral X fused to a telocentric Muller D and created the large neo-X (Muller A-AD) chromosome ∼15 MYA. We also confirm the fusion of Muller C and D in D. bifasciata and show that it likely involved a centromere-centromere fusion.

scholarly journals LRSDAY: Long-read Sequencing Data Analysis for Yeasts

2017 ◽  
Author(s):  
Jia-Xing Yue ◽  
Gianni Liti
Keyword(s):  
Genome Assembly ◽  
Model Organism ◽  
Sequencing Data ◽  
Protein Coding ◽  
Sequencing Technologies ◽  
Long Reads ◽  
Long Read ◽  
Downstream Analysis ◽  
Eukaryotic Organisms ◽  
Genomic Regions

AbstractLong-read sequencing technologies have become increasingly popular in genome projects due to their strengths in resolving complex genomic regions. As a leading model organism with small genome size and great biotechnological importance, the budding yeast, Saccharomyces cerevisiae, has many isolates currently being sequenced with long reads. However, analyzing long-read sequencing data to produce high-quality genome assembly and annotation remains challenging. Here we present LRSDAY, the first one-stop solution to streamline this process. LRSDAY can produce chromosome-level end-to-end genome assembly and comprehensive annotations for various genomic features (including centromeres, protein-coding genes, tRNAs, transposable elements and telomere-associated elements) that are ready for downstream analysis. Although tailored for S. cerevisiae, we designed LRSDAY to be highly modular and customizable, making it adaptable for virtually any eukaryotic organisms. Applying LRSDAY to a S. cerevisiae strain takes ∼43 hrs to generate a complete and well-annotated genome from ∼100X Pacific Biosciences (PacBio) reads using four threads.

scholarly journals A high-quality chromosome-level genome assembly reveals genetics for important traits in eggplant

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Qingzhen Wei ◽  
Jinglei Wang ◽  
Wuhong Wang ◽  
Tianhua Hu ◽  
Haijiao Hu ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Reference Genome ◽  
Repetitive Sequences ◽  
Gene Families ◽  
Specific Gene ◽  
High Quality ◽  
Total Size ◽  
Protein Coding ◽  
Fruit Length ◽  
Protein Coding Genes

Abstract Eggplant (Solanum melongena L.) is an economically important vegetable crop in the Solanaceae family, with extensive diversity among landraces and close relatives. Here, we report a high-quality reference genome for the eggplant inbred line HQ-1315 (S. melongena-HQ) using a combination of Illumina, Nanopore and 10X genomics sequencing technologies and Hi-C technology for genome assembly. The assembled genome has a total size of ~1.17 Gb and 12 chromosomes, with a contig N50 of 5.26 Mb, consisting of 36,582 protein-coding genes. Repetitive sequences comprise 70.09% (811.14 Mb) of the eggplant genome, most of which are long terminal repeat (LTR) retrotransposons (65.80%), followed by long interspersed nuclear elements (LINEs, 1.54%) and DNA transposons (0.85%). The S. melongena-HQ eggplant genome carries a total of 563 accession-specific gene families containing 1009 genes. In total, 73 expanded gene families (892 genes) and 34 contraction gene families (114 genes) were functionally annotated. Comparative analysis of different eggplant genomes identified three types of variations, including single-nucleotide polymorphisms (SNPs), insertions/deletions (indels) and structural variants (SVs). Asymmetric SV accumulation was found in potential regulatory regions of protein-coding genes among the different eggplant genomes. Furthermore, we performed QTL-seq for eggplant fruit length using the S. melongena-HQ reference genome and detected a QTL interval of 71.29–78.26 Mb on chromosome E03. The gene Smechr0301963, which belongs to the SUN gene family, is predicted to be a key candidate gene for eggplant fruit length regulation. Moreover, we anchored a total of 210 linkage markers associated with 71 traits to the eggplant chromosomes and finally obtained 26 QTL hotspots. The eggplant HQ-1315 genome assembly can be accessed at http://eggplant-hq.cn. In conclusion, the eggplant genome presented herein provides a global view of genomic divergence at the whole-genome level and powerful tools for the identification of candidate genes for important traits in eggplant.

scholarly journals Long-Read Genome Assembly of Saccharomyces uvarum Strain CBS 7001

2022 ◽  
Author(s):  
Jingxuan Chen ◽  
David J. Garfinkel ◽  
Casey M. Bergman
Keyword(s):  
Genome Assembly ◽  
Reference Genome ◽  
Sequence Data ◽  
Sensu Stricto ◽  
Whole Genome ◽  
Saccharomyces Uvarum ◽  
Content Type ◽  
Whole Genome Shotgun Sequence ◽  
Long Read ◽  
Genome Shotgun Sequence

Here, we report a long-read genome assembly for Saccharomyces uvarum strain CBS 7001 based on PacBio whole-genome shotgun sequence data. Our assembly provides an improved reference genome for an important yeast in the Saccharomyces sensu stricto clade.

scholarly journals Genome Sequence Data of Peronophythora litchii, an Oomycete Pathogen Causing Litchi Downy Blight

2021 ◽  
Author(s):  
Hengyuan Guo ◽  
Jiandong Bao ◽  
Lianyu Lin ◽  
Zhixin Wang ◽  
Mingyue Shi ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Sequence Data ◽  
Protein Coding ◽  
Rxlr Effectors ◽  
Oxford Nanopore ◽  
Long Read ◽  
Infection Mechanisms ◽  
Oomycete Pathogen ◽  
High Quality Genome ◽  
Oxford Nanopore Technologies

Peronophythora litchii is an oomycete pathogen that exclusively infects litchi, with infection stages affecting a broad range of tissues. In this study, we obtained a near chromosome-level genome assembly of P. litchii strain ZL2018 from China using Oxford Nanopore Technologies (ONT) long-read sequencing and Illumina short-read sequencing. The genome assembly was 64.15 Mb in size and consisted of 81 contigs with an N50 of 1.43 Mb and a maximum length of 4.74 Mb. Excluding 34.67% of repeat sequences, a total of 14,857 protein-coding genes were identified, among which 14,447 genes were annotated. We also predicted 306 candidate RXLR effectors in the assembly. The high-quality genome assembly and annotation resources reported in this study will provide new insight into the infection mechanisms of P. litchii.

scholarly journals Chromosome-level reference genome of the jellyfish Rhopilema esculentum

GigaScience ◽  
2020 ◽  
Vol 9 (4) ◽  
Author(s):  
Yunfeng Li ◽  
Lei Gao ◽  
Yongjia Pan ◽  
Meilin Tian ◽  
Yulong Li ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Evolutionary History ◽  
Reference Genome ◽  
Protein Coding ◽  
Fishery Resource ◽  
Rhopilema Esculentum ◽  
Sequencing Technologies ◽  
Genome Wide ◽  
History Of ◽  
Chromosome Level

Abstract Background Jellyfish belong to the phylum Cnidaria, which occupies an important phylogenetic location in the early-branching Metazoa lineages. The jellyfish Rhopilema esculentum is an important fishery resource in China. However, the genome resource of R. esculentum has not been reported to date. Findings In this study, we constructed a chromosome-level genome assembly of R. esculentum using Pacific Biosciences, Illumina, and Hi-C sequencing technologies. The final genome assembly was ∼275.42 Mb, with a contig N50 length of 1.13 Mb. Using Hi-C technology to identify the contacts among contigs, 260.17 Mb (94.46%) of the assembled genome were anchored onto 21 pseudochromosomes with a scaffold N50 of 12.97 Mb. We identified 17,219 protein-coding genes, with an average CDS length of 1,575 bp. The genome-wide phylogenetic analysis indicated that R. esculentum might have evolved more slowly than the other scyphozoan species used in this study. In addition, 127 toxin-like genes were identified, and 1 toxin-related “hub” was found by a genomic survey. Conclusions We have generated a chromosome-level genome assembly of R. esculentum that could provide a valuable genomic background for studying the biology and pharmacology of jellyfish, as well as the evolutionary history of Cnidaria.

scholarly journals Chromosome-level genome assembly of the African pike, Hepsetus odoe

2020 ◽  
Author(s):  
Xiao Du ◽  
Xiaoning Hong ◽  
Guangyi Fan ◽  
Xiaoyun Huang ◽  
Shuai Sun ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Freshwater Teleost ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Sequencing Technologies ◽  
Oxford Nanopore ◽  
Evolutionary Studies ◽  
Long Fragment Read ◽  
Representative Member ◽  
Chromosome Level

AbstractThe order Characiformes is one of the largest components of the freshwater teleost fauna inhabiting exclusively in South America and Africa with great ecological and economical significance. Yet, quite limited genomic resources are available to study this group and their transatlantic vicariance. In this study we present a chromosome-level genome assembly of the African pike (Hepsetus odoe), a representative member of the African Characiformes. To this end, we generated 119, 11, and 67 Gb reads using the single tube long fragment read (stLFR), Oxford Nanopore, and Hi-C sequencing technologies, respectively. We obtained an 862.1 Mb genome assembly with the contig and scaffold N50 of 347.4 kb and 25.8 Mb, respectively. Hi-C sequencing produced 29 chromosomes with 742.5 Mb, representing 86.1% of the genome. 24,314 protein-coding genes were predicted and 23,999 (98.7%) genes were functionally annotated. The chromosomal-scale genome assembly will be useful for functional and evolutionary studies of the African pike and promote the study of Characiformes speciation and evolution.

scholarly journals Pseudo-chromosome length genome assembly of a double haploid ‘Bartlett’ pear (Pyrus communis L.)

2019 ◽  
Author(s):  
Gareth Linsmith ◽  
Stephane Rombauts ◽  
Sara Montanari ◽  
Cecilia H. Deng ◽  
Jean-Marc Celton ◽  
...  
Keyword(s):  
Genome Assembly ◽  
Double Haploid ◽  
Repetitive Sequences ◽  
Chromosome Length ◽  
Pyrus Communis ◽  
Chromatin Interaction ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Pyrus Communis L ◽  
Long Read

AbstractWe report an improved assembly and scaffolding of the European pear (Pyrus communis L.) genome (referred to as BartlettDHv2.0), obtained using a combination of Pacific Biosciences RSII Long read sequencing (PacBio), Bionano optical mapping, chromatin interaction capture (Hi-C), and genetic mapping. A total of 496.9 million bases (Mb) corresponding to 97% of the estimated genome size were assembled into 494 scaffolds. Hi-C data and a high-density genetic map allowed us to anchor and orient 87% of the sequence on the 17 chromosomes of the pear genome. About 50% (247 Mb) of the genome consists of repetitive sequences. Comparison with previous assemblies of Pyrus communis and Pyrus x bretschneideri confirmed the presence of 37,445 protein-coding genes, which is 13% fewer than previously predicted.

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