• The KIPS Transactions:PartA
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• v.13A no.1 s.98
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• pp.79-86
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• 2006

Recently the tagSNP selection problem has been researched for reducing the cost of association studies between human's diversities and SNPs. General approach for this problem is that all of SNPs are separated into appropriate blocks and then tagSNPs are chosen in each block. Marsel in this paper is the system that involved the concept of linkage disequilibrium for overcoming the problem that the existing block partitioning approaches have short of biological meanings. In most approaches, the contiguous regions, which recombinations have LD coefficient |D'| and then tagSNP selection step is performed. And MarSel guarantees the minimum tagSNP selection using entropy-based optimal selection algorithm when tagSNPs are chosen in each block, and enables chromosome-level association studies using efficient memory management technique when input is very large-scale dataset that is impossible to be processed in the existing systems.

• Journal of applied mathematics & informatics
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• v.26 no.3_4
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• pp.493-500
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• 2008

In this paper, we first construct a mathematical model for tagSNP selection based on LD measure $r^2$, then aiming at this kind of model, we develop an efficient algorithm, which is called approximate greedy algorithm. This algorithm is able to make up the disadvantage of the greedy algorithm for tagSNP selection. The key improvement of our approximate algorithm over greedy algorithm lies in that it adds local replacement(or local search) into the greedy search, tagSNP is replaced with the other SNP having greater similarity degree with it, and the local replacement is performed several times for a tagSNP so that it can improve the tagSNP set of the local precinct, thereby improve tagSNP set of whole precinct. The computational results prove that our approximate greedy algorithm can always find more efficient solutions than greedy algorithm, and improve the tagSNP set of whole precinct indeed.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2004.11a
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• pp.279-285
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• 2004

In the disease association study, the tagSNP selection problem is important at the view of time and cost. We developed the new tagSNP selection system that has also facilities for the haplotype reconstruction and missing data processing. In our system, we improved biological meanings using LD coefficients as well as dynamic programming method. And our system has capability of processing large -scale dataset, such as the total SNPs on a chromosome. We have tested our system with various dataset from daly et al., patil et al., HapMap Project, artificial dataset, and so on.

• Journal of Plant Biotechnology
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• v.47 no.3
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• pp.218-226
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• 2020

This report describes methods for selecting informative single nucleotide polymorphisms (SNPs), and the development of an online Solanaceae genome database, using 234 tomato resequencing data entries deposited in the NCBI SRA database. The 126 accessions of Solanum lycopersicum, 68 accessions of Solanum lycopersicum var. cerasiforme, and 33 accessions of Solanum pimpinellifolium, which are frequently used for breeding, and some wild-species tomato accessions were included in the analysis. To select tag-SNPs, we identified 29,504,960 SNPs in 234 tomatoes and then separated the SNPs in the genic and intergenic regions according to gene annotation. All tag-SNP were selected from non-synonymous SNPs among the SNPs present in the gene region and, as a result, we obtained tag-SNP from 13,845 genes. When there were no non-synonymous SNPs in the gene, the genes were selected from synonymous SNPs. The total number of tag-SNPs selected was 27,539. To increase the usefulness of the information, a Solanaceae genome database website, TGsol (http://tgsol. seeders.co.kr/), was constructed to allow users to search for detailed information on resources, SNPs, haplotype, and tag-SNPs. The user can search the tag-SNP and flanking sequences for each gene by searching for a gene name or gene position through the genome browser. This website can be used to efficiently search for genes related to traits or to develop molecular markers.

• Development and Reproduction
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• v.18 no.4
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• pp.275-286
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• 2014

To successful molecular breeding, identification and functional characterization of breeding related genes and development of molecular breeding techniques using DNA markers are essential. Although the development of a useful marker is difficult in the aspect of time, cost and effort, many markers are being developed to be used in molecular breeding and developed markers have been used in many fields. Single nucleotide polymorphisms (SNPs) markers were widely used for genomic research and breeding, but has hardly been validated for screening functional genes in olive flounder. We identified single nucleotide polymorphisms (SNPs) from expressed sequence tag (EST) database in olive flounder; out of a total 4,327 ESTs, 693 contigs and 514 SNPs were detected in total EST, and these substitutions include 297 transitions and 217 transversions. As a result, 144 SNP markers were developed on the basis of 514 SNP to selection of useful gene region, and then applied to each of eight wild and culture olive flounder (total 16 samples). In our experimental result, only 32 markers had detected polymorphism in sample, also identified 21 transitions and 11 transversions, whereas indel was not detected in polymorphic SNPs. Heterozygosity of wild and cultured olive flounder using the 32 SNP markers is 0.34 and 0.29, respectively. In conclusion, we identified SNP and polymorphism in olive flounder using newly designed marker, it supports that developed markers are suitable for SNP detection and diversity analysis in olive flounder. The outcome of this study can be basic data for researches for immunity gene and characteristic with SNP.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.253-255
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• 2004

인간(human)에게 나타나는 다양성(variation)은 인체의 유전체(genome) 안에서 발생된 SNP(Single Nucleotide Polymorphism)에 의해 나타난다고 알려져 있다. 유전체내의 SNP과 다양성에 대한 연관 연구(Associate study)를 할 때에 약 30여 억 개로 추정되는 염기서열(DNA sequence)물 모두 분석한다면 많은 비용과 시간을 필요로 할 것이다. 이런 비용과 시간을 줄이기 위친 적은 수의 대표 SNP(=tagSNP)을 찾는 연구가 현재 진행 중이다. 우리는 LD계수｜D;｜을 block 분할에 이용하여 생물학적인 의미를 부여한 후, 전산적인 최적해를 찾는 접근을 이용했다. 또한, 기존 연구에서는 large-scale data에 대한 처리가 불가능해서 chromosome의 일부분의 데이터에 대해서안 분석이 시도되었다. 더욱 광범위한 분석을 위해서 chromosome 단위의 처리가 필요하다. 우리는 chromosome단위의 SNP data를 한 번에 처리가 가능한 시스템인 MarSel를 구현하였다

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.5
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• pp.628-635
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• 2018

Objective: To determine the effects of genomic breeding values (GBV) and single nucleotide polymorphisms (SNP) on the total number of piglets born (TNB) in 3 pig breeds (Berkshire, Landrace, and Yorkshire). Methods: After collecting genomic information (Porcine SNP BeadChip) and phenotypic TNB records for each breed, the effects of GBV and SNP were estimated by using single step best linear unbiased prediction (ssBLUP) method. Results: The heritability estimates for TNB in Berkshire, Landrace, and Yorkshire breeds were 0.078, 0.107, and 0.121, respectively. The breeding value estimates for TNB in Berkshire, Landrace, and Yorkshire breeds were in the range of -1.34 to 1.47 heads, -1.79 to 1.87 heads, and -2.60 to 2.94 heads, respectively. Of sows having records for TNB, the reliability of breeding value for individuals with SNP information was higher than that for individuals without SNP information. Distributions of the SNP effects on TNB did not follow gamma distribution. Most SNP effects were near zero. Only a few SNPs had large effects. The numbers of SNPs with absolute value of more than 4 standard deviations in Berkshire, Landrace, and Yorkshire breeds were 11, 8, and 19, respectively. There was no SNP with absolute value of more than 5 standard deviations in Berkshire or Landrace. However, in Yorkshire, four SNPs (ASGA 0089457, ASGA0103374, ALGA0111816, and ALGA0098882) had absolute values of more than 5 standard deviations. Conclusion: There was no common SNP with large effect among breeds. This might be due to the large genetic composition differences and the small size of reference population. For the precise evaluation of genetic performance of individuals using a genomic selection method, it may be necessary to establish the appropriate size of reference population.

• Korean Journal of Plant Resources
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• v.34 no.5
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• pp.443-450
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• 2021

Peach flesh color is commercially important criteria for classification and has implications for nutritional quality. To breed new yellow-fleshed peach cultivar many cross seedlings and generations should be maintained. Therefore it is necessary to develop early selection molecular markers for screening cross seedlings and germplasm with economically important traits to increase breeding efficiency. For the comparison of transcription profiles in peach varieties with a different flesh color expression, two cDNA libraries were constructed. Differences in gene expression between yellow-fleshed peach cultivar, 'Changhowon Hwangdo' and white-fleshed peach cultivar, 'Mibaekdo' were analyzed by next-generation sequencing (NGS). Expressed sequence tag (EST) of clones from the two varieties was selected for nucleotide sequence determination and homology searches. Putative single nucleotide polymorphisms (SNPs) were screened from peach EST contigs by high resolution melting (HRM) analysis, SNP ID ppa002847m:cds and ppa002540m:cds displayed specific difference between 17 yellow-fleshed and 21 white-fleshed peach varieties. The SNP markers for distinguishing yellow and white fleshed peach varieties by HRM analysis offers the opportunity to use early selection. This SNP markers could be useful for marker assisted breeding and provide a good reference for relevant research on molecular mechanisms of color variation in peach varieties.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.4
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• pp.485-493
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• 2019

Objective: This study was undertaken to investigate the genetic characteristics of Berkshire (BS), Landrace (LR), and Yorkshire (YS) pig breeds raised in the Great Grandparents pig farms using the single nucleotide polymorphisms (SNP) information. Methods: A total of 25,921 common SNP genotype markers in three pig breeds were used to estimate the expected heterozygosity ($H_E$), polymorphism information content, F-statistics ($F_{ST}$), linkage disequilibrium (LD) and effective population size ($N_e$). Results: The chromosome-wise distribution of $F_{ST}$ in BS, LR, and YS populations were within the range of 0-0.36, and the average $F_{ST}$ value was estimated to be $0.07{\pm}0.06$. This result indicated some level of genetic segregation. An average LD ($r^2$) for the BS, LR, and YS breeds was estimated to be approximately 0.41. This study also found an average $N_e$ of 19.9 (BS), 31.4 (LR), and 34.1 (YS) over the last 5th generations. The effective population size for the BS, LR, and YS breeds decreased at a consistent rate from 50th to 10th generations ago. With a relatively faster $N_e$ decline rate in the past 10th generations, there exists possible evidence for intensive selection practices in pigs in the recent past. Conclusion: To develop customized chips for the genomic selection of various breeds, it is important to select and utilize SNP based on the genetic characteristics of each breed. Since the improvement efficiency of breed pigs increases sharply by the population size, it is important to increase test units for the improvement and it is desirable to establish the pig improvement network system to expand the unit of breed pig improvement through the genetic connection among breed pig farms.

• Korean Journal of Plant Resources
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• v.32 no.4
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• pp.303-311
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• 2019

Various colors of fruit skin and flesh are the most popular commercial criteria for peach classification. In order to breed new red-fleshed peach cultivar, many cross seedlings and generations should be maintained. Therefore it is necessary to develop early selection markers to screen seedlings with target traits to increase breeding efficiency. For the comparison of transcription profiles in peach cultivars differing in flesh color expression, two cDNA libraries were constructed. Differences in gene expression between red-fleshed peach cultivar, 'Josanghyeoldo' and white-fleshed peach cultivar, 'Mibaekdo' were analyzed by next-generation sequencing (NGS). Expressed sequence tag (EST) of clones from the two cultivars were selected for nucleotide sequence determination and homology searches. Putative single nucleotide polymorphisms (SNP) were screened from peach EST contigs by high resolution melting (HRM) analysis displayed specific difference between 8 red-fleshed peach cultivars and 24 white-fleshed peach cultivars. All 72 pairs of SNPs were discriminated and the HRM profiles of amplicons were established. In the study reported here, the development of SNP markers for distinguishing between red and white fleshed peach cultivars by HRM analysis offers the opportunity to use DNA markers. This SNP marker could be useful for peach marker assisted breeding and provide a good reference for relevant research on molecular mechanisms of color variation in peach cultivars.