• Proceedings of the Korean Society for Bioinformatics Conference
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• 2005.09a
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• pp.113-117
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• 2005

In comparative genome analyses, synteny blocks play important roles for finding ortholog genes, reconstructing phylogenetic tree and predicting genome rearrangement events. In this paper, we propose a novel method to search biologically plausible synteny blocks not only from the viewpoint of finding highly preserved regions but also from the viewpoint of analyzing genome rearrangements. We have applied the method to our experiments on four fungal organisms, and succeeded to obtain some biologically interesting results.

• BMB Reports
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• v.45 no.6
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• pp.365-370
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• 2012

Hepatitis B virus (HBV) DNA is often integrated into hepatocellular carcinoma (HCC). Although the relationship between HBV integration and HCC development has been widely studied, the role of HBV integration in HCC development is still not completely understood. In the present study, we constructed a pooled BAC library of 9 established cell lines derived from HCC patients with HBV infections. By amplifying viral genes and superpooling of BAC clones, we identified 2 clones harboring integrated HBV DNA. Screening of host-virus junctions by repeated sequencing revealed an HBV DNA integration site on chromosome 11q13 in the SNU-886 cell line. The structure and rearrangement of integrated HBV DNA were extensively analyzed. An inverted duplicated structure, with fusion of at least 2 HBV DNA molecules in opposite orientations, was identified in the region. The gene expression of cancer-related genes increased near the viral integration site in HCC cell line SNU-886.

• Genomics & Informatics
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• v.8 no.2
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• pp.86-89
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• 2010

Closely related species share large genomic segments called syntenic regions, where the genomic elements such as genes are arranged co-linearly among the species. While synteny is an important criteria in establishing orthologous regions between species, non-syntenic regions may display species-specific features. As the first step in cataloging human- or primate- specific genomic elements, we surveyed human genomic regions that are not syntenic with any other non-primate mammalian genomes sequenced so far. Based on the data compiled in Ensembl databases, we were able to identify 10 such regions located in eight different human chromosomes. Interestingly, most of these highly human- or primate- specific loci are concentrated in subtelomeric or pericentromeric regions. It has been reported that subtelomeric regions in human chromosomes are highly plastic and filled with recently shuffled genomic elements. Pericentromeric regions also show a great deal of segmental duplications. Such genomic rearrangements may have caused these large human- or primate- specific genome segments.

• International Journal of Stem Cells
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• v.17 no.1
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• pp.1-14
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• 2024

The clustered regularly interspaced short palindromic repeats (CRISPR) system, a rapidly advancing genome editing technology, allows DNA alterations into the genome of organisms. Gene editing using the CRISPR system enables more precise and diverse editing, such as single nucleotide conversion, precise knock-in of target sequences or genes, chromosomal rearrangement, or gene disruption by simple cutting. Moreover, CRISPR systems comprising transcriptional activators/repressors can be used for epigenetic regulation without DNA damage. Stem cell DNA engineering based on gene editing tools has enormous potential to provide clues regarding the pathogenesis of diseases and to study the mechanisms and treatments of incurable diseases. Here, we review the latest trends in stem cell research using various CRISPR/Cas technologies and discuss their future prospects in treating various diseases.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.15-15
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• 2023

The chloroplast (cp) is an autonomous plant organelle with an individual genome that codes for essential cellular functions. The architecture and gene content of the cp genome is highly conserved in angiosperms. The plastome of Corydalis belongs to the Papaveraceae family, and the genome is comprised of unusual rearrangements and gene content. Thus far, no extensive comparative studies have been carried out to understand the evolution of Corydalis chloroplast genomes. Therefore, the Corydalis platycarpa cp genome was sequenced, and wide-scale comparative studies were conducted using publicly available twenty Corydalis plastomes. Comparative analyses showed that an extensive genome rearrangement and IR expansion occurred, and these events evolved independently in the Corydalis species. In addition, the protein-coding genes accD and the ndh gene loss events occurred in the common ancestor of the Corydalis and sub-clade of the Corydalis lineage, respectively. The gene ndh lost in the Corydalis-sub clade species is distributed predominantly in the Qinghai-Tibetan plateau (QTP) region. The molecular clock analysis suggests that the divergence time of all the ndh gene lost Corydalis sub-clade species occurred in the 44.31 - 15.71 mya. These results coincide very well with the uplift of the Qinghai-Tibet Plateau in the Oligocene and Miocene periods, and maybe during this period, it probably triggered the radiation of the Corydalis species. To the best of the authors' knowledge, this is the first large-scale comparative study of Corydalis plastomes and their evolution. The present study may provide insights into the plastome architecture and the molecular evolution of Corydalis species.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.2
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• pp.120-123
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• 1998

Based on the co-linearity in the Triticeae, comparative RFLP analysis of 2M chromosome of Ae. comosa Sibth et Sm. was performed with 2MS and 2M additional lines of Triticum aestivum L. cv. Chinese Spring. Among the wheat RFLP probes conserved in the short arms of wheat chromosome 2, those above psr912 were located on the long arms of 2M in Aegilops comosa. The rest probes on the short arm and all the probe sequences on the long arm of group 2 chromosome in wheat were conserved on the equivalent chromosomal position in Aegilops comosa. So, it is apparent that some chromosomal segment from the short arm had been transferred to long arm while reconstructing 2M chromosome relative to wheat chromosomes. The break-point was located between psr912 and psr131 of the short arm. This rearrangement of chromosome 2M might be a molecular evidence of the M genome speciation from an ancestral type.

• Genomics & Informatics
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• v.14 no.3
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• pp.70-77
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• 2016

Transposable elements are one of major sources to cause genomic instability through various mechanisms including de novo insertion, insertion-mediated genomic deletion, and recombination-associated genomic deletion. Among them is Alu element which is the most abundant element, composing ~10% of the human genome. The element emerged in the primate genome 65 million years ago and has since propagated successfully in the human and non-human primate genomes. Alu element is a non-autonomous retrotransposon and therefore retrotransposed using L1-enzyme machinery. The 'master gene' model has been generally accepted to explain Alu element amplification in primate genomes. According to the model, different subfamilies of Alu elements are created by mutations on the master gene and most Alu elements are amplified from the hyperactive master genes. Alu element is frequently involved in genomic rearrangements in the human genome due to its abundance and sequence identity between them. The genomic rearrangements caused by Alu elements could lead to genetic disorders such as hereditary disease, blood disorder, and neurological disorder. In fact, Alu elements are associated with approximately 0.1% of human genetic disorders. The first part of this review discusses mechanisms of Alu amplification and diversity among different Alu subfamilies. The second part discusses the particular role of Alu elements in generating genomic rearrangements as well as human genetic disorders.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.272-273
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• 2007

현대 유전체학 기술의 진보는 생물학적으로 중요한 의미를 갖는 생물들의 유전체 서열의 규명 genome sequencing)에 힘입은 바 크다. 기존의 유전체 서열결정법은 주로 염기변이율이 낮은 생물들에 초점을 맞추어 왔다. 하지만 염기변이율이 높은 생물들의 유전체 염기서열을 결정할 필요가 높아짐에 따라 이를 위한 방법론에 대한 연구가 활발히 진행되고 있다. 염기변이율이 높은 생물들의 이배체 (diploid) 유전체 서열이 효과적으로 결정될 수 있을 경우 기존의 유전체 서열비교의 방법론에도 변화가 요청되고 있는 실정이다. 기존의 유전체 서열비교 (whole-genome alignment) 방법론은 반수체 (haploid) 유전체들의 서열비교을 위해 개발되었지만, 염기변이율이 높은 생물들의 유전체 서열비교에는 반수체 유전체들 비교에 특화된 도구들이 필요하다. 또한 현재 서열비교를 시각화하는 소프트웨어들도 반수체 유전체 비교를 위해 개발된 실정이다. 본 논문의 목표는 이배체 유전체 서열을 비교하는 방법론을 개발을 용이하기위해 이배체 유전체의 서열을 생성하는 도구를 개발하는 것이다. 개발된 도구는 실제 일어날 수 있는 염기변이와 genomic rearrangement를 사용자의 입력을 받아 다수의 생물들의 유전체 서열을 생성해 낸다. 이를 통해 이배체 유전체 서열을 비교하는 도구의 개발을 용이하게 하는데 초첨을 맞추고 있다.

• Molecules and Cells
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• v.28 no.3
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• pp.155-165
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• 2009

The newly sequenced complete mitochondrial genome of the brown marmorated stink bug, Halyomorpha halys($St{\aa}l$) (Hemiptera: Pentatomidae), is a circular molecule of 16,518 bp with a total A+T content of 76.4% and two extensive repeat regions in A+T rich region. Nucleotide composition and codon usage of H. halys are about average when compared with values observed in 19 other published hemipteran mitochondrial genomes. Phylogenetic analyses using these 20 hemipteran mitochondrial genomes support the currently accepted hypothesis that suborders Heteroptera and Auchenorrhyncha form a monophyletic group. The mitochondrial gene arrangements of the 20 genomes are also consistent with our results.

• Molecules and Cells
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• v.23 no.2
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• pp.182-191
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• 2007

The complete mitochondrial genome of a troglobite millipede Antrokoreana gracilipes (Verhoeff, 1938) (Dipolopoda, Juliformia, Julida) was sequenced and characterized. The genome (14,747 bp) contains 37 genes (2 ribosomal RNA genes, 22 transfer RNA genes and 13 protein-encoding genes) and two large non-coding regions (225 bp and 31 bp), as previously reported for two diplopods, Narceus annularus (order Spirobolida) and Thyropygus sp. (order Spirostreptida). The A + T content of the genome is 62.1%, and four tRNAs ($tRNA^{Ser(AGN)}$, $tRNA^{Cys}$, $tRNA^{Ile}$ and $tRNA^{Met}$) have unusual and unstable secondary structures. Whereas Narceus and Thyropygus have identical gene arrangements, the $tRNA^{Thr}$ and $tRNA^{Trp}$ of Antrokoreana differ from them in their orientations and/or positions. This suggests that the Spirobolida and Spirostreptida are more closely related to each other than to the Dipolopoda. Three scenarios are proposed to account for the unique gene arrangement of Antrokoreana. The data also imply that the Duplication and Nonrandom Loss (DNL) model is applicable to the order Julida. Bayesian inference (BI) and maximum likelihood (ML) analyses using amino acid sequences deduced from the 12 mitochondrial protein-encoding genes (excluding ATP8) support the view that the three juliformian members are monophyletic (BI 100%; ML 100%), that Thyropygus (Spirostreptida) and Narceus (Spirobolida) are clustered together (BI 100%; ML 83%), and that Antrokoreana (Julida) is a sister of the two. However, due to conflict with previous reports using cladistic approaches based on morphological characteristics, further studies are needed to confirm the close relationship between Spirostreptida and Spirobolida.