• Proceedings of the Korean Society for Bioinformatics Conference
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• 2001.08a
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• pp.11-35
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• 2001

For the last twenty years fragment assembly in DNA sequencing followed the "overlap - layout - consensus"paradigm that is used in all currently available assembly tools. Although this approach proved to be useful in assembling clones, it faces difficulties in genomic shotgun assembly: the existing algorithms make assembly errors and are often unable to resolve repeats even in prokaryotic genomes. Biologists are well-aware of these errors and are forced to carry additional experiments to verify the assembled contigs. We abandon the classical “overlap - layout - consensus”approach in favor of a new Eulerian Superpath approach that, for the first time, resolves the problem of repeats in fragment assembly. Our main result is the reduction of the fragment assembly to a variation of the classical Eulerian path problem. This reduction opens new possibilities for repeat resolution and allows one to generate error-free solutions of the large-scale fragment assemble problems. The major improvement of EULER over other algorithms is that it resolves all repeats except long perfect repeats that are theoretically impossible to resolve without additional experiments.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.733-735
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• 2002

DNA fragment assembly 프로그램인 Phrap에서는 exact match를 찾기 위해 정렬된 k-글자 테이블 자료구조를 사용한다. 이것은 접미사 배열의 간단한 형태로서, DNA fragment assembly와 같은 응용에서는 접미사 배열보다 더 유용한 자료구조이다. 본 논문에서는 k-글자 테이블을 정렬하는 Manber-Myers, Quicksort, Radix sort 알고리즘을 살펴보고, 실험을 통해 그 중에서 가장 뛰어난 성능을 가지는 것이 Quicksort 알고리즘임을 보였다 또한 k-글자 테이블의 정렬 문제에 있어서는, 캐쉬-메모리 아키텍쳐에 최적화되어 계산복잡도 속에 숨어있는 상수를 최소화하는 것이 중요한 문제임을 밝힌다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.751-753
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• 2001

지금까지 인간이나 다른 생물체의 전체 유전체 염기서열을 밝혀내는 작업은 크게 세가지 방법으로 진행되었다. Clone-by-clone approach, sequence tagged connector approach, random shotgun approach[1]가 그것인데 마지막의 random shotgun approach는 fragment assembly problem을 비롯한 여러 가지 전산학적인 문제들을 수반한다. 미생물체의 전체 염기서열을 random shotgun approach를 이용하여 밝혀낼 때 몇 가지 전산학적인 문제가 테크닉이 필요하며 그 중에서도 서열간의 forward, reverse의 mating 정보를 이용하는 것이 중요하다. 본 논문은 이러한 mating 작업을 한 눈에 볼 수 있게 하는 소프트웨어 페키지 “Mater”에 대해 소개하고자 하며 그 의미에 대해 논하고자 한다.

• Genomics & Informatics
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• v.2 no.4
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• pp.184-190
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• 2004

An approach for genome analysis based on assembly of fragments of DNA from the whole genome can be applied to obtain the complete nucleotide sequence of the genome of Zymomonas mobilis. However, the problem of fragment assembly raise thorny computational issues. Computer simulation studies of sequence assembly usually show some abnormal assemblage of artificial sequences containing repetitive or duplicated regions, and suggest methods to correct those abnormalities. In this paper, we describe five simulation studies which had been performed previous to the actual genome assembly process of Zymomonas mobilis ZM4.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2002.06a
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• pp.105-121
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• 2002

최근 인간 지놈(genome)의 DNA가 밝혀져서 많은 관심을 받았는데, 이를 수행하는 방법을 소개한다. Human Genome Project에서 채택한 BAC-to-BAC 방식과 Celera 회사에서 채택한 whole genome shotgun 방식을 설명한다. 또한 두 방식에서 공히 fragment assembly 프로그램을 사용하는데, 이 프로그램의 개요를 설명한다.

• Microbiology and Biotechnology Letters
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• v.25 no.6
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• pp.560-565
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• 1997

DNA fragment assembly is a major concem in shot-gun DNA sequencing project. It is to reconstruct a consensus DNA sequence from a collection of random oritented fragments. We developed a computer program that is useful for DNA fragment assembly. Inputs to the program are DNA fragment sequences including IUB-IUPAC bases. The program produces the most probable reconstruction ot the original DNA sequence as a text format or a PostScript format. The program consists of four phases: the first phase quickly eliminates fragment pairs that can not possibly overlap. In the second phase, the quality of overlap between each pair is calculated to a score. In the third phase, overlap pairs are sorted by their scores and consistency of the overlaps is checked. The last phase determines consensus sequences and displays them. The performance of fragment assembly program was tested on a set of DNA fragment sequences which were generated from long DNA sequences of GenBank by a fragmentation program.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.7 s.250
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• pp.841-848
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• 2006

Many researchers are developing computational prediction methods for protein tertiary structures to get much more information of protein. These methods are very attractive on the aspects of breaking technologies of computer hardware and simulation software. One of the computational methods for the prediction is a fragment assembly method which shows good ab initio predictions at several cases. There are many barriers, however, in conventional fragment assembly methods. Argues on protein energy functions and global optimization to predict the structures are in progress fer example. In this study, a new prediction method for protein structures is proposed. The proposed method mainly consists of two parts. The first one is a fragment assembly which uses very shot fragments of representative proteins and produces a prototype of a given sequence query of amino acids. The second one is a global optimization which folds the prototype and makes the only protein structure. The goodness of the proposed method is shown through numerical experiments.

• Genomics & Informatics
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• v.7 no.1
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• pp.46-48
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• 2009

Finishing is the most time-consuming step in sequencing, and many genome projects are left unfinished due to complex repeat regions. Here, we have developed BACContigEditor, a prototype shotgun sequence finishing tool. It is essentially an editor that visualizes assemblies of shotgun sequence fragment reads as gapped multiple alignments. The program offers some flexibility that is needed to rapidly resolve complex regions within a working session. The sole purpose of the release is to promote collaborative creation of extensible software for fragment assembly editors, foster collaborative development, and reduce barriers to initial tool development effort. We describe our software architecture and identify current challenges. The program is available under an Open Source license.

• The Plant Pathology Journal
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• v.32 no.3
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• pp.173-181
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• 2016

Gene disruption by homologous recombination is widely used to investigate and analyze the function of genes in Fusarium fujikuroi, a fungus that causes bakanae disease and root rot symptoms in rice. To generate gene deletion constructs, the use of conventional cloning methods, which rely on restriction enzymes and ligases, has had limited success due to a lack of unique restriction enzyme sites. Although strategies that avoid the use of restriction enzymes have been employed to overcome this issue, these methods require complicated PCR steps or are frequently inefficient. Here, we introduce a cloning system that utilizes multi-fragment assembly by In-Fusion to generate a gene disruption construct. This method utilizes DNA fragment fusion and requires only one PCR step and one reaction for construction. Using this strategy, a gene disruption construct for Fusarium cyclin C1 (FCC1), which is associated with fumonisin B1 bio-synthesis, was successfully created and used for fungal transformation. In vivo and in vitro experiments using confirmed fcc1 mutants suggest that fumonisin production is closely related to disease symptoms exhibited by F. fujikuroi strain B14. Taken together, this multi-fragment assembly method represents a simpler and a more convenient process for targeted gene disruption in fungi.

• Proceedings of the PSK Conference
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• 2003.10a
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• pp.90-90
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• 2003

I describe here a novel and promising approach to drug discovery that involves the identification and assembly of drug-like fragments to afford lead compounds. This approach is attractive for a number of reasons. First, the productive assembly of two weakly bound fragments, even fragments with independent dissociation constants in the low mM range, can potentially afford ligands with sub-micromolar affinities for their targets. (omitted)