• BMB Reports
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• v.40 no.3
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• pp.419-425
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• 2007

In vitro directed evolution through DNA shuffling is a powerful molecular tool for creation of new biological phenotypes. E. coli $\beta$-galactosidase and $\beta$-glucuronidase are widely used, and their biological function, catalytic mechanism, and molecular structures are well characterized. We applied an in vitro directed evolution strategy through DNA shuffling and obtained five mutants named YG6764, YG6768, YG6769, YG6770 and YG6771 after two rounds of DNA shuffling and screening, which exhibited more $\beta$-glucuronidase activity than wild-type $\beta$-galactosidase. These variants had mutations at fourteen nucleic acid sites, resulting in changes in ten amino acids: S193N, T266A, Q267R, V411A, D448G, G466A, L527I, M543I, Q626R and Q951R. We expressed and purified those mutant proteins. Compared to the wild-type protein, five mutant proteins exhibited high $\beta$-glucuronidase activity. The comparison of molecular models of the mutated and wildtype enzymes revealed the relationship between protein function and structural modification.

• Development and Reproduction
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• v.25 no.1
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• pp.25-32
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• 2021

The main purpose of the current study was to obtain nuclear DNA content data among the representatives of the families and subfamilies of 31 endemic fishes that inhabit river of Korea. DNA contents of 31 endemic species were observed to rang from 1.5 to 4.8 pg DNA/nucleus. In Cyprinidae, DNA content of Abbottina springeri (1.5±0.03 pg DNA/nucleus) was the lowest value and DNA content of Carassius cuvieri (4.5±0.32 pg DNA/nucleus) was the highest value in all experimental groups. In Cobitidae, DNA content of Iksookimia longicorpa (3.9±0.17 pg DNA/nucleus) was the highest value and DNA content of Orthrias toni (1.5±0.18 pg DNA/nucleus) was the lowest value in all experimental groups. This study provides new information for a better understanding of the process of genomic evolution in 31 endemic species in river of Korea.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.225-228
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• 2001

DNA computing has been applied to the problem of getting an optimal solution since Adleman's experiment. DNA computing uses strings with various length and four-type bases that makes more useful for finding a global optimal solutions of the complex multi-modal problems. This paper presents DNA coding method for finding optimal solution of the multi-modal function and compares the efficiency of this method with the genetic algorithms (GA). GA searches effectively an optimal solution via the artificial evolution of individual group of binary string and DNA coding method uses a tool of calculation or Information store with DNA molecules and four-type bases denoted by the symbols of A(Ademine), C(Cytosine), G(Guanine) and T(Thymine). The same operators, selection, crossover, mutation, are applied to the both DNA coding algorithm and genetic algorithms. The results show that the DNA based algorithm performs better than GA.

• Genomics & Informatics
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• v.14 no.1
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• pp.29-33
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• 2016

A retron is a bacterial retroelement that encodes an RNA gene and a reverse transcriptase (RT). The former, once transcribed, works as a template primer for reverse transcription by the latter. The resulting DNA is covalently linked to the upstream part of the RNA; this chimera is called multicopy single-stranded DNA (msDNA), which is extrachromosomal DNA found in many bacterial species. Based on the conserved features in the eight known msDNA sequences, we developed a detection method and applied it to scan National Center for Biotechnology Information (NCBI) RefSeq bacterial genome sequences. Among 16,844 bacterial sequences possessing a retron-type RT domain, we identified 48 unique types of msDNA. Currently, the biological role of msDNA is not well understood. Our work will be a useful tool in studying the distribution, evolution, and physiological role of msDNA.

• Fisheries and Aquatic Sciences
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• v.9 no.2
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• pp.70-74
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• 2006

DNA sequence-based typing is considered a robust tool for the discrimination of dinoflagellate species because of the availability of extensive rDNA sequences. Here, we present a rapid, cost-effective DNA-sequencing technique for various PCR products. This sequencing strategy relies on 'nested' or 'tailed' primer labeled with near-infrared dye, and uses a minimal volume of unpurified PCR product (ca. $5{\mu}L$) as the DNA template for sequencing reactions. Reliable and accurate base identification was obtained for several hundred PCR fragments of rRNA genes. This quick, inexpensive technique is widely applicable to sequence-based typing in clinical applications, as well as to large-scale DNA sequencing of the same genomic regions from related species for studies of molecular evolution.

• BMB Reports
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• v.38 no.4
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• pp.386-390
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• 2005

Based on the reported cDNA sequences of $BmK{\alpha}Txs$, the genes encoding toxin $BmK{\alpha}Tx11$ and $BmK{\alpha}Tx15$ were amplified by PCR from the Chinese scorpion Buthus martensii Karsch genomic DNA employing synthetic oligonucleotides. Sequences analysis of nucleotide showed that an intron about 500 bp length interrupts signal peptide coding regions of $BmK{\alpha}Tx11$ and $BmK{\alpha}Tx15$. Using cDNA sequence of $BmK{\alpha}Tx11$ as probe, southern hybridization of BmK genome total DNA was performed. The result indicates that $BmK{\alpha}Tx11$ is multicopy genes or belongs to multiple gene family with high homology genes. The similarity of $BmK{\alpha}$-toxin gene sequences and southern hybridization revealed the evolution trace of $BmK{\alpha}$-toxins: $BmK{\alpha}$-toxin genes evolve from a common progenitor, and the genes diversity is associated with a process of locus duplication and gene divergence.

• Animal Systematics, Evolution and Diversity
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• v.37 no.3
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• pp.229-234
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• 2021

Scolelepis (Scolelepis) daphoinos is newly reported in Korean fauna. This species can be distinguished from its congeners by the following characteristics: the presence of reddish pigment patches on the posterior part of the prostomium, notopodial postchaetal lamellae that are partially fused to the branchiae, and the presence of only the bidentate hooded hooks. The morphological diagnosis and photographs of S. (S.) daphoinos are provided. The partial mitochondrial cytochrome c oxidase subunit I (COI), 16S ribosomal DNA(16S rDNA), and the nuclear 18S ribosomal DNA (18S rDNA) sequences from Korean specimens of S. (S.) daphoinos were determined. Species identification was supported by a comparison of DNA barcode sequences of COI and 16S rDNA with morphological examination from the specimens of type locality, China.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.456-459
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• 1999

In this paper, we propose a new neural network based on the DNA coding method. The initial population of the structure information and the weights for the neural network is generated, and then the descendants are chose with the Elitist selection by the genetic algorithm. The evolutionary technique and the suitable fitness measure are used to find a neural network with the fractal number of layers. which represents a good approximation to the given function.

• Animal Systematics, Evolution and Diversity
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• v.13 no.1
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• pp.21-27
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• 1997

한국 고유종인 새코미꾸리(Cobitis rotundicaudata)의 집단간 유전적 차이에 따른 종 분화 여부를 밝히고자 4개집단을 대상으로mitochondrial DNA(mtDNA)의 RFLP분석을 실시 하였다. C. rotundicaudata mtDNA를 10개의 6-base cutting 제한요소로 처리한 다음 그 절 편 양상을 비교, 분석한 결과 4개 집단 공히 mtDNA의 전체 genome 크기는 약 16.5$\pm$ 0.5Kbp였으며 공통절편수(F)에서 한강 2개 집단(가평, 진부)과 동해안 마읍천 짐단간의 F값 은 0.911로 매우 가까웠으나 낙동강의 산청집단은 타 3개 집단과 F=0.375로 차이가 있었다. 또한 염기치환율(p)에 있어서도 한강 2개 집단 및 마읍천 집단간은 평균 p=0.005로 매우 유 사하였으나, 산청 집단은 타 집단들과 염기치환율에 있어 p=0.059로 종수준의 뚜렷한 차이 를 나타내어서 이들은 각각 별종으로 사료된다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2002.12a
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• pp.383-386
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• 2002

In this paper, we investigated the pattern recognition performance of the numeric patterns (from 0 to 9) using DNA coding method. The pattern recognition performance of the DNA coding method is compared to the that of the GA(Genetic Algorithm). GA searches effectively an optimal solution via the artificial evolution of individual group of binary string using binary coding, while DNA coding method uses four-type bases denoted by A(Adenine), C(Cytosine), G(Guanine) and T(Thymine), The pattern recognition performance of GA and DNA coding method is evaluated by using the same genetic operators(crossover and mutation) and the crossover probability and mutation probability are set the same value to the both methods. The DNA coding method has better characteristics over genetic algorithms (GA). The reasons for this outstanding performance is multiple possible solution presentation in one string and variable solution string length.