• Genomics & Informatics
• /
• v.19 no.3
• /
• pp.32.1-32.10
• /
• 2021

Semisulcospira libertina, a species of freshwater snail, is widespread in East Asia. It is important as a food source. Additionally, it is a vector of clonorchiasis, paragonimiasis, metagonimiasis, and other parasites. Although S. libertina has ecological, commercial, and clinical importance, its whole-genome has not been reported yet. Here, we revealed the genome of S. libertina through de novo assembly. We assembled the whole-genome of S. libertina and determined its transcriptome for the first time using Illumina NovaSeq 6000 platform. According to the k-mer analysis, the genome size of S. libertina was estimated to be 3.04 Gb. Using RepeatMasker, a total of 53.68% of repeats were identified in the genome assembly. Genome data of S. libertina reported in this study will be useful for identification and conservation of S. libertina in East Asia.

• Genomics & Informatics
• /
• v.10 no.1
• /
• pp.1-8
• /
• 2012

Recently, the technologies of DNA sequence variation and gene expression profiling have been used widely as approaches in the expertise of genome biology and genetics. The application to genome study has been particularly developed with the introduction of the nextgeneration DNA sequencer (NGS) Roche/454 and Illumina/ Solexa systems, along with bioinformation analysis technologies of whole-genome $de$ $novo$ assembly, expression profiling, DNA variation discovery, and genotyping. Both massive whole-genome shotgun paired-end sequencing and mate paired-end sequencing data are important steps for constructing $de$ $novo$ assembly of novel genome sequencing data. It is necessary to have DNA sequence information from a multiplatform NGS with at least $2{\times}$ and $30{\times}$ depth sequence of genome coverage using Roche/454 and Illumina/Solexa, respectively, for effective an way of de novo assembly. Massive shortlength reading data from the Illumina/Solexa system is enough to discover DNA variation, resulting in reducing the cost of DNA sequencing. Whole-genome expression profile data are useful to approach genome system biology with quantification of expressed RNAs from a wholegenome transcriptome, depending on the tissue samples. The hybrid mRNA sequences from Rohce/454 and Illumina/Solexa are more powerful to find novel genes through $de$ $novo$ assembly in any whole-genome sequenced species. The $20{\times}$ and $50{\times}$ coverage of the estimated transcriptome sequences using Roche/454 and Illumina/Solexa, respectively, is effective to create novel expressed reference sequences. However, only an average $30{\times}$ coverage of a transcriptome with short read sequences of Illumina/Solexa is enough to check expression quantification, compared to the reference expressed sequence tag sequence.

• BMB Reports
• /
• v.49 no.12
• /
• pp.653-654
• /
• 2016

The human reference genome, maintained by the Genome Reference Consortium, is conceivably the most complete genome assembly ever, since its first construction. It has continually been improved by incorporating corrections made to the previous assemblies, thanks to various technological advances. Many currently-ongoing population sequencing projects have been based on this reference genome, heightening hopes of the development of useful medical applications of genomic information, thanks to the recent maturation of high-throughput sequencing technologies. However, just one reference genome does not fit all the populations across the globe, because of the large diversity in genomic structures and technical limitations inherent to short read sequencing methods. The recent success in de novo construction of the highly contiguous Asian diploid genome AK1, by combining single molecule technologies with routine sequencing data without resorting to traditional clone-by-clone sequencing and physical mapping, reveals the nature of genomic structure variation by detecting thousands of novel structural variations and by finally filling in some of the prior gaps which had persistently remained in the current human reference genome. Now it is expected that the AK1 genome, soon to be paired with more upcoming de novo assembled genomes, will provide a chance to explore what it is really like to use ancestry-specific reference genomes instead of hg19/hg38 for population genomics. This is a major step towards the furthering of genetically-based precision medicine.

• KIISE Transactions on Computing Practices
• /
• v.20 no.9
• /
• pp.513-518
• /
• 2014

It has become possible for small scale laboratories to interpret large scale genomic DNA, thanks to the reduction of the sequencing cost by the development of next generation sequencing (NGS). De novo assembly is a method which creates a putative original sequence by reconstructing reads without using a reference sequence. There have been various study results on de novo assembly, however, it is still difficult to get the desired results even by using the same assembly procedures and the analysis tools which were suggested in the studies reported. This is mainly because there are no specific guidelines for the assembly procedures or know-hows for the use of such analysis tools. In this study, to resolve these problems, we introduce steps to finding whole genome of an unknown DNA via NGS technology and de novo assembly, while providing the pros and cons of the various analysis tools used in each step. We used 350Mbp of Toxocara canis DNA as an application case for the detailed explanations of each stated step. We also extend our works for prediction of protein-coding genes and their functions from the draft genome sequence by comparing its homology with reference sequences of other nematodes.

• Journal of the Korea Society of Computer and Information
• /
• v.25 no.8
• /
• pp.1-8
• /
• 2020

In this paper, we propose a gene family based RNA-seq read distribution method in means to accelerate the overal transcriptome assembly computation time. To measure the performance of our transcriptome sequence data distribution method, we evaluated the performance by testing four types of data sets of the Arabidopsis thaliana genome (Whole Unclassified Reads, Family-Classified Reads, Model-Classified Reads, and Randomly Classified Reads). As a result of de novo transcript assembly in distributed nodes using model classification data, the generated gene contigs matched 95% compared to the contig generated by WUR, and the execution time was reduced by 4.2 times compared to a single node environment using the same resources.

• Genomics & Informatics
• /
• v.6 no.2
• /
• pp.87-90
• /
• 2008

During the last four years, the pyrosequencing-based 454 platform has rapidly displaced the traditional Sanger sequencing method due to its high throughput and cost effectiveness. Meanwhile, the Sanger sequencing methodology still provides the longest reads, and paired-end sequencing that is based on that chemistry offers an opportunity to ensure accurate assembly results. In this report, we describe an optimized approach for hybrid de novo genome assembly using pyrosequencing data and varying amounts of Sanger-type reads. 454 platform-derived contigs can be used as single non-breakable virtual reads or converted to simpler contigs that consist of editable, overlapping pseudoreads. These modified contigs maintain their integrity at the first jumpstarting assembly stage and are edited by fragmenting and rejoining. Pre-existing assembly software then can be applied for mixed assembly with 454-derived data and Sanger reads. An effective method for identifying genomic differences between reference and sample sequences in whole-genome resequencing procedures also is suggested.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.28-28
• /
• 2022

This paper presents the first genome assemblies of Philippine mangoes that provide valuable reference for varietal improvement and genomic studies on mango and related fruit crops. WE sequenced whole genomes of3 species, Mangifera odorata (Huani), Mangifera altissima (Paho), and Mangifera indica 'Carabao' (Sweet Elena). 'Carabao' is the major export variety of the Philippines; Paho is identified as vulnerable by the IUCN Red List of Threatened Species; Huani has fruit sap acrid which is the primary defense mechanism against insects and birds. We used Falcon, a diploid aware -de novo assembler to assemble SMRT generated long-read sequences. Falcon-unzip was employed to phase the output assembly producing larger contig sets (primary contigs) and shorter contigs corresponding to haplotypes (haplotigs). Assembly statistics were generated by comparing the assembly to a reference genome, Tommy Atkins, using Quality Assessment Tool (QUAST). Moreover, the extent of duplication and completeness of gene content was measured using Benchmarking Universal Single-Copy Orthologs (BUSCO). Draft assemblies with high duplications were processed using Purge Haplotigs and Purge Dups to lessen duplications with minimal impact on genome completeness. De novo assemblies of Huani, Paho and 'Carabao' were then generated with primary contig sizes of 463.64 Mb, 508.95 Mb and 401.51 Mb respectively. These draft assemblies of Huani, Paho and 'Carabao' showed 96.90%, 95.17% and 99.07% complete BUSCOs respectively which is comparable to 'Tommy Atkins' genome (98.6%). Using two mango transcriptome data (pooled RNA-seq from different mango varieties and tissues), 91-96% or 24-30 million reads were successfully mapped back for each generated assembly indicating high degree of completeness. The results obtained demonstrated the highly contiguous, phased, and near complete genome assembly of three Philippine mango species for structural and functional annotation of gene units, especially those with economic importance.

• The Plant Pathology Journal
• /
• v.33 no.5
• /
• pp.478-487
• /
• 2017

Soybean is the most important legume crop in the world. Several diseases in soybean lead to serious yield losses in major soybean-producing countries. Moreover, soybean can be infected by diverse viruses. Recently, we carried out a large-scale screening to identify viruses infecting soybean using available soybean transcriptome data. Of the screened transcriptomes, a soybean transcriptome for soybean seed development analysis contains several virus-associated sequences. In this study, we identified five viruses, including soybean mosaic virus (SMV), infecting soybean by de novo transcriptome assembly followed by blast search. We assembled a nearly complete consensus genome sequence of SMV China using transcriptome data. Based on phylogenetic analysis, the consensus genome sequence of SMV China was closely related to SMV isolates from South Korea. We examined single nucleotide variations (SNVs) for SMVs in the soybean seed transcriptome revealing 780 SNVs, which were evenly distributed on the SMV genome. Four SNVs, C-U, U-C, A-G, and G-A, were frequently identified. This result demonstrated the quasispecies variation of the SMV genome. Taken together, this study carried out bioinformatics analyses to identify viruses using soybean transcriptome data. In addition, we demonstrated the application of soybean transcriptome data for virus genome assembly and SNV analysis.

• Parasites, Hosts and Diseases
• /
• v.54 no.6
• /
• pp.751-758
• /
• 2016

This study aimed at constructing a draft genome of the adult female worm Toxocara canis using next-generation sequencing (NGS) and de novo assembly, as well as to find new genes after annotation using functional genomics tools. Using an NGS machine, we produced DNA read data of T. canis. The de novo assembly of the read data was performed using SOAPdenovo. RNA read data were assembled using Trinity. Structural annotation, homology search, functional annotation, classification of protein domains, and KEGG pathway analysis were carried out. Besides them, recently developed tools such as MAKER, PASA, Evidence Modeler, and Blast2GO were used. The scaffold DNA was obtained, the N50 was 108,950 bp, and the overall length was 341,776,187 bp. The N50 of the transcriptome was 940 bp, and its length was 53,046,952 bp. The GC content of the entire genome was 39.3%. The total number of genes was 20,178, and the total number of protein sequences was 22,358. Of the 22,358 protein sequences, 4,992 were newly observed in T. canis. Following proteins previously unknown were found: E3 ubiquitin-protein ligase cbl-b and antigen T-cell receptor, zeta chain for T-cell and B-cell regulation; endoprotease bli-4 for cuticle metabolism; mucin 12Ea and polymorphic mucin variant C6/1/40r2.1 for mucin production; tropomodulin-family protein and ryanodine receptor calcium release channels for muscle movement. We were able to find new hypothetical polypeptides sequences unique to T. canis, and the findings of this study are capable of serving as a basis for extending our biological understanding of T. canis.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.32-32
• /
• 2022

Abaca (Musa textilis L. Nee) is a native Musa species from the Philippines known for its natural fiber. Abaca fiber a.k.a. Manila hemp extracted from its pseudostems is considered one of the strongest fibers in the world. This is used for commodities such as ropes, papers, and money bills. Abaca is vulnerable to pests and diseases such as the Abaca Bunchy Top Disease (ABTD) caused by Abaca Bunchy Top Virus (ABTV) and Banana Bunchy Top Virus (BBTV). Inosa, one of the varieties of abaca utilized in the Philippines, is highly susceptible to ABTD. In contrast, Pacol (Musa balbisiana L.), a close relative of abaca, is highly resistant to the same disease. Here, we report the sequencing and de novo genome assembly of both abaca var. Inosa and banana var. Pacol. A total of ~16 Gb and ~21 Gb raw reads for Inosa and Pacol, respectively, were generated using Pacbio Hifi sequencing method and assembled with Hifiasm. High-quality de novo assemblies of both Musa species with 99% recovered as per BUSCO analysis were obtained. The assembled Inosa genome has a total length of ~654 Mb and N50 of 7 Mb while Pacol has a total length of 527 Mb and N50 of 3 Mb which are close to their estimated genome size of ~638 Mb and ~503 Mb, respectively. The information that can be derived from the de novo assembled genomes would provide a solid foundation for further research in disease resistance and fiber quality improvement in abaca.