scholarly journals Insights from the first genome assembly of Onion (Allium cepa)

2021 ◽  
Author(s):  
Richard Finkers ◽  
Martijn van Kaauwen ◽  
Kai Ament ◽  
Karin Burger-Meijer ◽  
Raymond Egging ◽  
...  
Keyword(s):  
Ab Initio ◽  
De Novo ◽  
Gene Prediction ◽  
Repetitive Sequences ◽  
Linkage Maps ◽  
Vegetable Crop ◽  
Putative Gene ◽  
Final Assembly ◽  
Genetic Linkage Maps ◽  
High Quality Genome

Abstract Onion is an important vegetable crop with an estimated genome size of 16 Gb. We describe the de novo assembly and ab initio annotation of the genome of a doubled haploid onion line DHCU066619, which resulted in a final assembly of 14.9 Gb with a N50 of 464 Kb. Of this, 2.4 Gb was ordered into 8 pseudomolecules using four genetic linkage maps. The remainder of the genome is available in 89.6 K scaffolds. Only 72.4% of the genome could be identified as repetitive sequences and consist, to a large extent, of (retro) transposons. In addition, an estimated 20% of the putative (retro) transposons had accumulated a large number of mutations, hampering their identification, but facilitating their assembly. These elements are probably already quite old. The ab initio gene prediction indicated 540,925 putative gene models, which is far more than expected, possibly due to the presence of pseudogenes. Of these models, 47,066 showed RNASeq support. No gene rich regions were found, genes are uniformly distributed over the genome. Analysis of synteny with A. sativum (garlic) showed collinearity but also major rearrangements between both species. This assembly is the first high-quality genome sequence available for the study of onion and will be a valuable resource for further research.

scholarly journals Insights from the first genome assembly of Onion (Allium cepa)

2021 ◽  
Author(s):  
Richard Finkers ◽  
Martijn P.W. van Kaauwen ◽  
Kai Ament ◽  
Karin Burger-Meijer ◽  
Raymond J. Egging ◽  
...  
Keyword(s):  
Ab Initio ◽  
Genetic Linkage ◽  
De Novo ◽  
Gene Prediction ◽  
Draft Genome ◽  
Linkage Maps ◽  
Vegetable Crop ◽  
Putative Gene ◽  
Final Assembly ◽  
Genetic Linkage Maps

Onion is an important vegetable crop with an estimated genome size of 16GB. We describe the de novo assembly and ab initio annotation of the genome of a doubled haploid onion line DHCU066619, which resulted in a final assembly of 14.9 Gb with a N50 of 461 Kb. Of which 2.2 Gb was ordered into 8 pseudomolecules using five genetic linkage maps. The remainder of the genome is available in 89.8 K scaffolds. Analysis of this genome shows that at least 72.4% of the genome is repetitive and consists, to a large extent, of (retro) transposons. Many (retro) transposons were already quite old as they had accumulated many mutations, facilitating their assembly, however, hampering their identification. The draft ab initio gene prediction indicated 540 925 putative gene models, which is far more than expected, possibly due to the presence of pseudogenes. 86,073 models showed similarity to published proteins (UNIPROT). No gene rich regions were found, genes are uniformly distributed over the genome. Analysis of synteny with A. sativum (garlic) showed collinearity but also major rearrangements between both species. Not-withstanding, this assembly is the first high-quality draft genome sequence available for the study of onion and will be a valuable resource for further research.

scholarly journals The First Draft Genome Assembly of Snow Sheep (Ovis nivicola)

2020 ◽  
Vol 12 (8) ◽  
pp. 1330-1336 ◽  
Author(s):  
Maulik Upadhyay ◽  
Andreas Hauser ◽  
Elisabeth Kunz ◽  
Stefan Krebs ◽  
Helmut Blum ◽  
...  
Keyword(s):  
De Novo ◽  
Gene Annotation ◽  
Gene Prediction ◽  
Repetitive Sequences ◽  
Draft Genome ◽  
Single Copy ◽  
Climatic Conditions ◽  
Draft Genome Assembly ◽  
Sheep Genome ◽  
Long Reads

Abstract The snow sheep, Ovis nivicola, which is endemic to the mountain ranges of northeastern Siberia, are well adapted to the harsh cold climatic conditions of their habitat. In this study, using long reads of Nanopore sequencing technology, whole-genome sequencing, assembly, and gene annotation of a snow sheep were carried out. Additionally, RNA-seq reads from several tissues were also generated to supplement the gene prediction in snow sheep genome. The assembled genome was ∼2.62 Gb in length and was represented by 7,157 scaffolds with N50 of about 2 Mb. The repetitive sequences comprised of 41% of the total genome. BUSCO analysis revealed that the snow sheep assembly contained full-length or partial fragments of 97% of mammalian universal single-copy orthologs (n = 4,104), illustrating the completeness of the assembly. In addition, a total of 20,045 protein-coding sequences were identified using comprehensive gene prediction pipeline. Of which 19,240 (∼96%) sequences were annotated using protein databases. Moreover, homology-based searches and de novo identification detected 1,484 tRNAs; 243 rRNAs; 1,931 snRNAs; and 782 miRNAs in the snow sheep genome. To conclude, we generated the first de novo genome of the snow sheep using long reads; these data are expected to contribute significantly to our understanding related to evolution and adaptation within the Ovis genus.

scholarly journals Twelve quick steps for genome assembly and annotation in the classroom

2020 ◽  
Vol 16 (11) ◽  
pp. e1008325
Author(s):  
Hyungtaek Jung ◽  
Tomer Ventura ◽  
J. Sook Chung ◽  
Woo-Jin Kim ◽  
Bo-Hye Nam ◽  
...  
Keyword(s):  
Genome Assembly ◽  
De Novo ◽  
Repetitive Sequences ◽  
Genome Project ◽  
Model Organisms ◽  
High Quality ◽  
Sequencing Technologies ◽  
A Genome ◽  
Sequencing Platforms ◽  
High Quality Genome

Eukaryotic genome sequencing and de novo assembly, once the exclusive domain of well-funded international consortia, have become increasingly affordable, thus fitting the budgets of individual research groups. Third-generation long-read DNA sequencing technologies are increasingly used, providing extensive genomic toolkits that were once reserved for a few select model organisms. Generating high-quality genome assemblies and annotations for many aquatic species still presents significant challenges due to their large genome sizes, complexity, and high chromosome numbers. Indeed, selecting the most appropriate sequencing and software platforms and annotation pipelines for a new genome project can be daunting because tools often only work in limited contexts. In genomics, generating a high-quality genome assembly/annotation has become an indispensable tool for better understanding the biology of any species. Herein, we state 12 steps to help researchers get started in genome projects by presenting guidelines that are broadly applicable (to any species), sustainable over time, and cover all aspects of genome assembly and annotation projects from start to finish. We review some commonly used approaches, including practical methods to extract high-quality DNA and choices for the best sequencing platforms and library preparations. In addition, we discuss the range of potential bioinformatics pipelines, including structural and functional annotations (e.g., transposable elements and repetitive sequences). This paper also includes information on how to build a wide community for a genome project, the importance of data management, and how to make the data and results Findable, Accessible, Interoperable, and Reusable (FAIR) by submitting them to a public repository and sharing them with the research community.

scholarly journals A Hybridde novoAssembly of the Sea Pansy (Renilla muelleri) Genome

2018 ◽  
Author(s):  
Justin Jiang ◽  
Andrea M. Quattrini ◽  
Warren R. Francis ◽  
Joseph F. Ryan ◽  
Estefanía Rodríguez ◽  
...  
Keyword(s):  
De Novo ◽  
Gene Prediction ◽  
Draft Genome ◽  
Three Dimensional ◽  
Deep Ocean ◽  
Gene Families ◽  
Celera Assembler ◽  
Final Assembly ◽  
Hybrid Genome ◽  
Reporter Assays

AbstractBackgroundOver 3,000 species of octocorals (Cnidaria, Anthozoa) inhabit an expansive range of environments, from shallow tropical seas to the deep-ocean floor. They are important foundation species that create coral “forests” which provide unique niches and three-dimensional living space for other organisms. The octocoral genusRenillainhabits sandy, continental shelves in the subtropical and tropical Atlantic and eastern Pacific Oceans.Renillais especially interesting because it produces secondary metabolites for defense, exhibits bioluminescence, and produces a luciferase that is widely used in dual-reporter assays in molecular biology. Although several cnidarian genomes are currently available, the majority are from hexacorals. Here, we present ade novoassembly of theR. muellerigenome, making this the first complete draft genome from an octocoral.FindingsWe generated a hybridde novoassembly using the Maryland Super-Read Celera Assembler v.3.2.6 (MaSuRCA). The final assembly included 4,825 scaffolds and a haploid genome size of 172 Mb. A BUSCO assessment found 88% of metazoan orthologs present in the genome. An Augustusab initiogene prediction found 23,660 genes, of which 66% (15,635) had detectable similarity to annotated genes from the starlet sea anemone,Nematostella vectensis,or to the Uniprot database. Although theR. muellerigenome is smaller (172 Mb) than other publicly available, hexacoral genomes (256-448 Mb), theR. muellerigenome is similar to the hexacoral genomes in terms of the number of complete metazoan BUSCOs and predicted gene models.ConclusionsTheR. muellerihybrid genome provides a novel resource for researchers to investigate the evolution of genes and gene families within Octocorallia and more widely across Anthozoa. It will be a key resource for future comparative genomics with other corals and for understanding the genomic basis of coral diversity.

scholarly journals First de novo whole genome sequencing and assembly of the bar-headed goose

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8914 ◽  
Author(s):  
Wen Wang ◽  
Fang Wang ◽  
Rongkai Hao ◽  
Aizhen Wang ◽  
Kirill Sharshov ◽  
...  
Keyword(s):  
High Altitude ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Genome Assembly ◽  
De Novo ◽  
Gene Prediction ◽  
Repetitive Sequences ◽  
Gene Families ◽  
Whole Genome ◽  
Sequencing Data

Background The bar-headed goose (Anser indicus) mainly inhabits the plateau wetlands of Asia. As a specialized high-altitude species, bar-headed geese can migrate between South and Central Asia and annually fly twice over the Himalayan mountains along the central Asian flyway. The physiological, biochemical and behavioral adaptations of bar-headed geese to high-altitude living and flying have raised much interest. However, to date, there is still no genome assembly information publicly available for bar-headed geese. Methods In this study, we present the first de novo whole genome sequencing and assembly of the bar-headed goose, along with gene prediction and annotation. Results 10X Genomics sequencing produced a total of 124 Gb sequencing data, which can cover the estimated genome size of bar-headed goose for 103 times (average coverage). The genome assembly comprised 10,528 scaffolds, with a total length of 1.143 Gb and a scaffold N50 of 10.09 Mb. Annotation of the bar-headed goose genome assembly identified a total of 102 Mb (8.9%) of repetitive sequences, 16,428 protein-coding genes, and 282 tRNAs. In total, we determined that there were 63 expanded and 20 contracted gene families in the bar-headed goose compared with the other 15 vertebrates. We also performed a positive selection analysis between the bar-headed goose and the closely related low-altitude goose, swan goose (Anser cygnoides), to uncover its genetic adaptations to the Qinghai-Tibetan Plateau. Conclusion We reported the currently most complete genome sequence of the bar-headed goose. Our assembly will provide a valuable resource to enhance further studies of the gene functions of bar-headed goose. The data will also be valuable for facilitating studies of the evolution, population genetics and high-altitude adaptations of the bar-headed geese at the genomic level.

scholarly journals Reference Quality Assembly of the 3.5 Gb genome of Capsicum annuum from a Single Linked-Read Library

2017 ◽  
Author(s):  
Amanda M. Hulse-Kemp ◽  
Shamoni Maheshwari ◽  
Kevin Stoffel ◽  
Theresa A. Hill ◽  
David Jaffe ◽  
...  
Keyword(s):  
Capsicum Annuum ◽  
De Novo ◽  
Repetitive Sequences ◽  
Complete Recovery ◽  
Plant Genomes ◽  
Final Assembly ◽  
Eukaryotic Genes ◽  
Reference Quality ◽  
Pepper Genome ◽  
Genome Assemblies

AbstractBackgroundLinked-Read sequencing technology has recently been employed successfully for de novo assembly of multiple human genomes, however the utility of this technology for complex plant genomes is unproven. We evaluated the technology for this purpose by sequencing the 3.5 gigabase (Gb) diploid pepper (Capsicum annuum) genome with a single Linked-Read library. Plant genomes, including pepper, are characterized by long, highly similar repetitive sequences. Accordingly, significant effort is used to ensure the sequenced plant is highly homozygous and the resulting assembly is a haploid consensus. With a phased assembly approach, we targeted a heterozygous F1 derived from a wide cross to assess the ability to derive both haplotypes for a pungency gene characterized by a large insertion/deletion.ResultsThe Supernova software generated a highly ordered, more contiguous sequence assembly than all currently available C. annuum reference genomes. Eighty-four percent of the final assembly was anchored and oriented using four de novo linkage maps. A comparison of the annotation of conserved eukaryotic genes indicated the completeness of assembly. The validity of the phased assembly is further demonstrated with the complete recovery of both 2.5 kb insertion/deletion haplotypes of the PUN1 locus in the F1 sample that represents pungent and non-pungent peppers.ConclusionsThe most contiguous pepper genome assembly to date has been generated through this work which demonstrates that Linked-Read library technology provides a rapid tool to assemble de novo complex highly repetitive heterozygous plant genomes. This technology can provide an opportunity to cost-effectively develop high-quality reference genome assemblies for other complex plants and compare structural and gene differences through accurate haplotype reconstruction.

scholarly journals Comparative Genomics Analysis of Repetitive Elements in Ten Gymnosperm Species: “Dark Repeatome” and Its Abundance in Conifer and Gnetum Species

Life ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1234
Author(s):  
Avi Titievsky ◽  
Yuliya A. Putintseva ◽  
Elizaveta A. Taranenko ◽  
Sofya Baskin ◽  
Natalia V. Oreshkova ◽  
...  
Keyword(s):  
Picea Glauca ◽  
De Novo ◽  
Repetitive Sequences ◽  
Repetitive Elements ◽  
Genomic Sequencing ◽  
Taxus Baccata ◽  
Pinus Sibirica ◽  
Sequencing Data ◽  
Final Assembly ◽  
Biological Taxa

Repetitive elements (RE) and transposons (TE) can comprise up to 80% of some plant genomes and may be essential for regulating their evolution and adaptation. The “repeatome” information is often unavailable in assembled genomes because genomic areas of repeats are challenging to assemble and are often missing from final assembly. However, raw genomic sequencing data contain rich information about RE/TEs. Here, raw genomic NGS reads of 10 gymnosperm species were studied for the content and abundance patterns of their “repeatome”. We utilized a combination of alignment on databases of repetitive elements and de novo assembly of highly repetitive sequences from genomic sequencing reads to characterize and calculate the abundance of known and putative repetitive elements in the genomes of 10 conifer plants: Pinus taeda, Pinus sylvestris, Pinus sibirica, Picea glauca, Picea abies, Abies sibirica, Larix sibirica, Juniperus communis, Taxus baccata, and Gnetum gnemon. We found that genome abundances of known and newly discovered putative repeats are specific to phylogenetically close groups of species and match biological taxa. The grouping of species based on abundances of known repeats closely matches the grouping based on abundances of newly discovered putative repeats (kChains) and matches the known taxonomic relations.

scholarly journals De novo assembly of trachidermus fasciatus genome by nanopore sequencing

2020 ◽  
Author(s):  
Gangcai Xie ◽  
Xu Zhang ◽  
Feng Lv ◽  
Mengmeng Sang ◽  
Hairong Hu ◽  
...  
Keyword(s):  
Reference Genome ◽  
De Novo ◽  
Gene Prediction ◽  
Protein Coding ◽  
De Novo Gene ◽  
Long Reads ◽  
Resource Protection ◽  
Trachidermus Fasciatus ◽  
Roughskin Sculpin ◽  
High Quality Genome

AbstractTrachidermus fasciatus is a roughskin sculpin fish widely located at the coastal areas of East Asia. Due to the environmental destruction and overfishing, the populations of this species have been under threat. It is important to have a reference genome to study the population genetics, domestic farming, and genetic resource protection. However, currently, there is no reference genome for Trachidermus fasciatus, which has greatly hurdled the studies on this species. In this study, we proposed to integrate nanopore long reads sequencing, Illumina short reads sequencing and Hi-C methods to thoroughly de novo assemble the genome of Trachidermus fasciatus. Our results provided a chromosome-level high quality genome assembly with a total length of about 543 Mb, and with N50 of 23 Mb. Based on de novo gene prediction and RNA sequencing information, a total of 38728 genes were found, including 23191 protein coding genes, 2149 small RNAs, 5572 rRNAs, and 7816 tRNAs. Besides, about 23% of the genome area is covered by the repetitive elements. Furthermore, The BUSCO evaluation of the completeness of the assembled genome is more than 96%, and the single base accuracy is 99.997%. Our study provided the first whole genome reference for the species of Trachidermus fasciatus, which might greatly facilitate the future studies on this species.

scholarly journals VfODB: a comprehensive database of ESTs, EST-SSRs, mtSSRs, microRNA-target markers and genetic maps in Vicia faba

AoB Plants ◽  
2020 ◽  
Vol 12 (6) ◽  
Author(s):  
Morad M Mokhtar ◽  
Ebtissam H A Hussein ◽  
Salah El-Din S El-Assal ◽  
Mohamed A M Atia
Keyword(s):  
Vicia Faba ◽  
Faba Bean ◽  
Expressed Sequence Tags ◽  
Genetic Linkage ◽  
Genetic Maps ◽  
Linkage Maps ◽  
Microrna Target ◽  
Genetic Linkage Maps ◽  
Expressed Sequence ◽  
Simple Sequence

Abstract Faba bean (Vicia faba) is an essential food and fodder legume crop worldwide due to its high content of proteins and fibres. Molecular markers tools represent an invaluable tool for faba bean breeders towards rapid crop improvement. Although there have historically been few V. faba genome resources available, several transcriptomes and mitochondrial genome sequence data have been released. These data in addition to previously developed genetic linkage maps represent a great resource for developing functional markers and maps that can accelerate the faba bean breeding programmes. Here, we present the Vicia faba Omics database (VfODB) as a comprehensive database integrating germplasm information, expressed sequence tags (ESTs), expressed sequence tags-simple sequence repeats (EST-SSRs), and mitochondrial-simple sequence repeats (mtSSRs), microRNA-target markers and genetic maps in faba bean. In addition, KEGG pathway-based markers and functional maps are integrated as a novel class of annotation-based markers/maps. Collectively, we developed 31 536 EST markers, 9071 EST-SSR markers and 3023 microRNA-target markers based on V. faba RefTrans V2 mining. By mapping 7940 EST and 2282 EST-SSR markers against the KEGG pathways database we successfully developed 107 functional maps. Also, 40 mtSSR markers were developed based on mitochondrial genome mining. On the data curation level, we retrieved 3461 markers representing 12 types of markers (CAPS, EST, EST-SSR, Gene marker, INDEL, Isozyme, ISSR, RAPD, SCAR, RGA, SNP and SSR), which mapped across 18 V. faba genetic linkage maps. VfODB provides two user-friendly tools to identify, classify SSR motifs and in silico amplify their targets. VfODB can serve as a powerful database and helpful platform for faba bean research community as well as breeders interested in Genomics-Assisted Breeding.

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