• 정보과학회 논문지
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• 제45권3호
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• pp.200-210
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• 2018

여러 DNA 리드 시퀀스가 주어졌을 때, de novo 시퀀스 어셈블리는 레퍼런스 시퀀스 없이 하나의 시퀀스를 재조립한다. 재조립을 위해 de novo 시퀀스 어셈블리는 리드 사이의 모든 겹침을 계산하는 overlap 단계가 필요하다. Overlap 단계는 전체 연산 중 비용이 가장 많이 들기 때문에 어셈블리의 계산 성능을 좌우한다. 여러 분야에서 overlap 단계를 위한 연구가 많이 발표되고 있는데, 그 중 가장 최신의 세 연구 결과는 Readjoiner, SOF, Lim-Park 알고리즘이다. 최근 염기 분석기술의 큰 발전으로 DNA 리드 데이터 셋을 기존보다 저비용으로 대량 생산하는 것이 가능해져 DNA 리드 데이터 셋을 생성하는 여러 플랫폼들이 개발되었다. 각 플랫폼마다 생성하는 데이터 셋의 통계적 특성이 다르기 때문에 overlap 단계의 성능 평가 시 다양한 통계적 특성의 데이터 셋이 반영되어야 한다. 본 논문은 여러 통계적 특성을 가진 DNA 리드 데이터 셋을 이용하여 위의 세 알고리즘의 성능을 비교 분석한다.

• 한국컴퓨터정보학회논문지
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• 제25권8호
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• pp.1-8
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• 2020

본 논문에서는 드노보 전사체 어셈블리의 수행시간을 단축하기 위해 RNA-seq 서열을 유전자계 정보를 활용하여 여러 노드로 분산이 가능한 방법을 제시한다. 제안하는 전사체 서열 데이터 분산기법의 성능을 측정하기 위해 애기장대의 리드를 4개의 데이터 셋(전체 비분류 리드, 완전 분류 리드, 모델 분류 리드, 무작위 분류 리드)으로 구성하여 실험을 수행하였다. 전체 비분류 데이터와 비교하여 생성된 유전자 콘티그(Contig)는 95% 일치하였고 동일한 리소스들을 사용하는 단일 노드에 비해 본 연구에서 제시하는 분산환경분산 환경 기반의 어셈블리 수행시간은 4.2배 단축되었다.

• Journal of Plant Biotechnology
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• 제43권3호
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• pp.293-301
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• 2016

High-quality gene sets are necessary for functional research of genes. Although Perilla is a commonly cultivated oil crop and vegetable crop in Southeast Asia, the quality of its available gene set is insufficient. To construct a high-quality Perilla gene set, we sequenced mRNAs extracted from different tissues of Perilla citriodora, the wild species (2n = 20) of Perilla. To make a high-quality gene set for P. citriodora, we compared the quality of assemblies produced by Velvet and Trinity, the two well-known de novo assemblers, and improved the de novo assembly pipeline by optimizing k-mers and removing redundant sequences. We then selected representative transcripts for loci according to several criteria. The improved assembly yielded a total of 86,396 transcripts and 38,413 representative transcripts. We evaluated the assembled transcripts by comparing them to 638 homologous Arabidopsis genes involved in fatty acid and TAG biosynthesis pathways. High proportions of full-length genes and transcripts in the assembled transcripts matched known genes in other species, indicating that the P. citriodora gene set can be applied in future functional studies. Our study provides a reference P. citriodora gene set for further studies. It will serve as valuable genetic resource to elucidate the molecular basis of various metabolisms.

• Genomics & Informatics
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• 제10권1호
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• pp.1-8
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• 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.

• Genomics & Informatics
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• 제19권3호
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• pp.32.1-32.10
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• 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.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제20권9호
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• pp.513-518
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• 2014

NGS 기술의 발달로 시퀀싱 비용이 급격히 하락됨에 따라 대규모 크기의 유전체 염기 서열해독을 소규모의 실험실에서 수행할 수 있게 되었다. 디노버 어셈블리는 표준 유전체가 없는 새로운 종을 시퀀싱하는 경우 리드들의 염기 서열 정보를 이용하여 재구성함으로써 원래의 전체 시퀀스를 복원하는 것이다. 최근 이와 관련된 많은 연구 결과가 보고되고 있으나, 충분한 분석 노하우와 명확한 가이드라인 등이 공개되어 있지 않기 때문에 이들 연구에서 제시하는 동일한 어셈블리 수행 과정 및 분석 툴들을 사용하더라도 만족할만한 수준의 어셈블리 결과를 얻지 못하는 경우가 발생한다. 본 연구에서는 이러한 문제점을 해결하기 위하여 NGS 기술과 디노버 어셈블리 기술을 이용하여 아직 밝혀지지 않은 생물체의 전체 DNA의 염기 서열을 밝히기 위한 일련의 과정들을 단계별로 소개하고, 각 단계에서 필요로 하는 공개용 분석 툴의 장단점을 분석하여 제시한다. 이러한 과정별 단계를 구체적으로 설명하기 위하여 본 연구에서는 350Mbp 크기의 개 회충 게놈을 응용 사례로 사용한다. 또한 디노버 어셈블리 과정을 통해 새롭게 어셈블리된 시퀀스와 다른 유사 종과의 상동성 분석을 수행하여 어셈블리된 시퀀스에서의 유전자 영역 추출과 추출된 유전자의 기능을 예측한다.

• BMB Reports
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• 제49권12호
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• pp.653-654
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• 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.

• Genomics & Informatics
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• 제17권3호
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• pp.27.1-27.9
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• 2019

Supernumerary B chromosomes were found in Lilium amabile (2n = 2x = 24), an endemic Korean lily that grows in the wild throughout the Korean Peninsula. The extra B chromosomes do not affect the host-plant morphology; therefore, whole transcriptome analysis was performed in 0B and 1B plants to identify differentially expressed genes. A total of 154,810 transcripts were obtained from over 10 Gbp data by de novo assembly. By mapping the raw reads to the de novo transcripts, we identified 7,852 differentially expressed genes (log₂FC > |10|), in which 4,059 and 3,794 were up-and down-regulated, respectively, in 1B plants compared to 0B plants. Functional enrichment analysis revealed that various differentially expressed genes were involved in cellular processes including the cell cycle, chromosome breakage and repair, and microtubule formation; all of which may be related to the occurrence and maintenance of B chromosomes. Our data provide insight into transcriptomic changes and evolution of plant B chromosomes and deliver an informative database for future study of B chromosome transcriptomes in the Korean lily.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 춘계학술발표회
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• pp.5-5
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• 2018

Ginseng (Panax ginseng C.A. Meyer), one of the most widely used medicinal plants in traditional oriental medicine, is used for the treatment of various diseases. It has been classified according to its cultivation environment, such as field cultivated ginseng (FCG) and mountain cultivated ginseng (MCG). However, little is known about differences in gene expression in ginseng roots between field cultivated and mountain cultivated ginseng. In order to investigate the whole transcriptome landscape of ginseng, we employed High-Throughput sequencing technologies using the Illumina HiSeqTM2500 system, and generated a large amount of sequenced transcriptome from ginseng roots. Approximately 77 million and 87 million high-quality reads were produced in the FCG and MCG roots transcriptome analyses, respectively, and we obtained 256,032 assembled unigenes with an average length of 1,171 bp by de novo assembly methods. Functional annotations of the unigenes were performed using sequence similarity comparisons against the following databases: the non-redundant nucleotide database, the InterPro domains database, the Gene Ontology Consortium database, and the Kyoto Encyclopedia of Genes and Genomes pathway database. A total of 4,207 unigenes were assigned to specific metabolic pathways, and all of the known enzymes involved in starch and sucrose metabolism pathways were also identified in the KEGG library. This study indicated that alpha-glucan phosphorylase 1, putative pectinesterase/pectinesterase inhibitor 17, beta-amylase, and alpha-glucan phosphorylase isozyme H might be important factors involved in starch and sucrose metabolism between FCG and MCG in different environments.

• Parasites, Hosts and Diseases
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• 제54권6호
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• pp.751-758
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• 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.