• Genomics & Informatics
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• v.9 no.4
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• pp.189-193
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• 2011

Simple sequence repeats (SSRs) are ubiquitous short tandem duplications found within eukaryotic genomes. Their length variability and abundance throughout the genome has led them to be widely used as molecular markers for crop-breeding programs, facilitating the use of marker-assisted selection as well as estimation of genetic population structure. Here, we report a software application, "SSR-Primer Generator " for SSR discovery, SSR-primer design, and homology-based search of in silico amplicons from a DNA sequence dataset. On submission of multiple FASTA-format DNA sequences, those analyses are batch processed in a Java runtime environment (JRE) platform, in a pipeline, and the resulting data are visualized in HTML tabular format. This application will be a useful tool for reducing the time and costs associated with the development and application of SSR markers.

• Korean Journal of Plant Tissue Culture
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• v.24 no.2
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• pp.113-117
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• 1997

Simple sequence repeats (SSR) are widely dispersed throughout eukaryotic genomes, highly polymorphic, and easily typed using polymerase chain reaction (PCR). The objective of this study was to determine the polymorphism of different Chlamydomonas reinhartdtii strains and to determine the mode of inheritance of the SSR locus in Chlamydomonas. A genomic DNA library of C. reinhardtii was constructed and screened with a radiolabeled $(AC)_{11}$ probe for the selection of (CA/GT)n repeat clone. Selected clone was seqeuenced, and PCR primer set flanking (CA/GT)n sequence was constructed. PCR was used to specifically amplify the SSR locus from multiple isolates of C. reinhardtii. The locus was polymorphic in some of the C. reinhardtii isolates. However, the locus was amplified only 4 of 6 isolates of C. reinhardtii, not in other 2 isolates of C. reinhardtii, suggesting that this locus is not extensively conserved. A simple Mendelian inheritance pattern was found, which showed 2:2 segregation in the tetrads resulting from a cross between C. reinhardtii and C. smithii. Our results suggest that this simple sequence repeat DNA polymorphism will be useful for identity testing, population studies, linkage analysis, and genome mapping in Chlamydomonas.

• Horticultural Science & Technology
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• v.30 no.3
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• pp.278-285
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• 2012

Cymbidium goeringii is one of the most important and popular species in the orchid family in north-east Asia. In the present study, we prepared multiplex PCR system, and used it for the genotyping of eight simple sequence repeats (SSR) markers (CG409, CG415, CG709, CG722, CG787, CG1023, CG1210, and CG1281) in subject with 40 samples of cultivated varieties. All the analyzed samples showed different combined genotypes. The average combined power of discrimination was very high value of $7.14{\times}10^{-10}$, and observed heterozygosity (Ho = 0.466) was similar with two wild populations of C. goeringii, which may indicate no or little occurrence of genetic change after collection from wild habitats. The present study also developed a two-dimensional barcode to express information of genotype results of eight SSR markers (SSR DNA ID). The discrimination power of DNA ID between two individuals will be statistically more than 99.999999%. The SSR DNA ID and two-dimensional barcode may be very usefully applied for the discrimination and maintence of cultivars of C. goeringii.

• Journal of Mushroom
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• v.19 no.4
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• pp.341-346
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• 2021

Simple sequence repeats (SSRs) were isolated from major Pleurotus pulmonarius cultivars in Korea, namely 'HS47' (monokaryon, gamete of 'Santari'), 'GB19' (monokaryon, gamete of 'Santari'), 'Hosan,' 'Yeoleumneutali1,' 'Sambok,' 'Gangsan,' 'Yaksan,' 'Jasan,' 'Hyangsan,' and 'Yeoleumneutali2,' and characterized via HiSeq genome sequencing and bioinformatic analysis. The genome sizes of the monokaryons 'HS47' and 'GB19' were estimated to be 37.3 and 37.2 Mb, respectively, and those of the other dikaryotic cultivars ranged from 47.1 to 61.1 Mb. A total of 711 (smallest) and 1,106 (1.5 times the smallest) SSRs were found in the 'HS47' and 'Gangsan' genomes, respectively. Hexanucleotide and octanucleotide motifs accounted for the top two fractions of all SSRs. CGA/TCG, A/T, and CTC/GAG were the most frequently detected nucleotides in the SSRs. Most of the SSRs were 21~30 nucleotides long (hypervariable for application), accounting for 70% of all lengths of SSRs.

• Journal of Mushroom
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• v.14 no.4
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• pp.174-178
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• 2016

Simple sequence repeats (SSR), also referred to "microsatellites" consist of tandemly repeated short DNA sequence motifs and have been applied in various marker-based studies. SSRs were isolated and characterized from 'Heuktari' and 'Miso', which are major oyster mushroom cultivars in Korea, by genome sequencing and bioinformatic analysis. The genome sizes of 'Heuktari' and 'Miso' were estimated to be 40.8 and 40.3 Mb, respectively, which are larger than those of other P. ostreatus species (PC9 and PC10) and smaller than those of P. eryngii (KNR2312P5). In total, 949 and 968 SSRs were found in the 'Heuktari' and 'Miso' genomes, respectively. Comparative analysis of five mushrooms including P. ostreatus var. florida (PC9 and PC15) and P. eryngii revealed that the number of SSRs in 'Heuktari' and 'Miso' were the highest among them. All mushrooms studied showed similar SSR distribution patterns. Tri-, hexa-, and octanucleotide motifs accounted for the top three fractions of all SSRs.

• Journal of Korean Society of Forest Science
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• v.87 no.3
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• pp.422-428
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• 1998

Polymerase chain reaction(PCR)-based inter-simple sequence repeats(I-SSR) markers were analyzed in 48 megagametophytes of a single tree of Abies koreana $W_{ILS}$. Nineteen of the 35 primers, screened with 6 megagametophyte DNA and produced the clearest amplification products in the preliminary experiment, were used for PCR with 48 megagametophyte DNAs sampled from a single tree. On the basis of the chi-square test, a total of 51 amplicons, amplified by the 19 primers, were revealed to be segregated according to the Mendelian ratio(i.e., 1 : 1 segregation ratio) in the 48 megagametophytes at 5% significance level. Based on the linkage analysis, the observed 51 Mendelian loci turned out to be unlinked each other, which suggested that they are evenly distributed in the genome. However, majority of RAPD markers are known to belong to the independent linkage blocks, which frequently results in the amplification of RAPD markers from the restricted regions of the genome. Owing to the nature of even distribution of the 51 loci observed in this study, the I-SSR markers could give better resolution of estimating genetic diversity from the whole genome than RAPD markers. And I-SSR markers are also more suitable than RAPD markers for reconstructing phylogenetic relationship by a cladistic method which requires to fulfil the assumption of independent evolution of the different characters.

• Molecules and Cells
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• v.23 no.3
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• pp.349-356
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• 2007

Simple Sequence Repeats (SSRs) represent short tandem duplications found within all eukaryotic organisms. To examine the distribution of SSRs in the genome of Brassica rapa ssp. pekinensis, SSRs from different genomic regions representing 17.7 Mb of genomic sequence were surveyed. SSRs appear more abundant in non-coding regions (86.6%) than in coding regions (13.4%). Comparison of SSR densities in different genomic regions demonstrated that SSR density was greatest within the 5'-flanking regions of the predicted genes. The proportion of different repeat motifs varied between genomic regions, with trinucleotide SSRs more prevalent in predicted coding regions, reflecting the codon structure in these regions. SSRs were also preferentially associated with gene-rich regions, with peri-centromeric heterochromatin SSRs mostly associated with retrotransposons. These results indicate that the distribution of SSRs in the genome is non-random. Comparison of SSR abundance between B. rapa and the closely related species Arabidopsis thaliana suggests a greater abundance of SSRs in B. rapa, which may be due to the proposed genome triplication. Our results provide a comprehensive view of SSR genomic distribution and evolution in Brassica for comparison with the sequenced genomes of A. thaliana and Oryza sativa.

• Journal of Plant Biotechnology
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• v.7 no.1
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• pp.17-25
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• 2005

We have mined each of the five A. thaliana chromosomes for the presence of simple sequence repeats (SSRs) and developed custom perl scripts to examine their distribution and abundance in relation to genomic position, local G/C content and location within and around transcribed sequences. The distribution of repeats and G/C content with respect to genomic regions (exons, UTRs, introns, intergenic regions and proximity to expressed genes) are shown. SSRs show a non-random distribution across the genome and a strong association within and around transcribed sequences, while G/C density is associated specifically with the coding portions of transcribed sequences. SSR motif repeat number shows a high degree of variation for each SSR type and a high degree of motif sequence bias reflecting local genome sequence composition. PCR primers suitable for the amplification of identified SSRs have been designed where possible, and are available for further studies.

• Korean Journal of Veterinary Service
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• v.41 no.4
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• pp.257-262
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• 2018

Avian pathogenic E. coli (APEC) causes severe economic losses in the poultry farms, due to systemic infections leading to lethal colisepticemia. It causes a variety of diseases from air sac infection to systemic spread leading to septicemia. Secondary infection contains opportunistic infections due to immunosuppression disease. Collibacillosis causes the great problems in the poultry industry in Korea. Thus, it is necessary to identify and classify the characteristics of E. coli isolate of chicken origin to confirm the diversity of symptoms and whether they are transmitted among the farms. Fragment analysis is identify the difference in the number of Variable-Number Tandem-Repeats (VNTRs) for genotyping. VNTRs have repeating structure (Microsatellite, Short tandem repeats; STR, Simple sequence repeats; SSR) in the chromosome. This region can be used as a genetic marker because of its high mutation rate. And various lengths of the amplified DNA fragment cause the difference in the number of repetition of the DNA specific site. The number of repetition sequences indicates the separated size of fragments, so the each fragments can be distinguished by specific samples. The results of the sample show that there is no difference in six microsatellite loci (yjiD, aidB, molR_1, ftsZ, b1668, yibA). There are differences among the farms in relation of the number of repetitions of other six microsatellite loci (ycgW, yaiN, yiaB, mhpR, b0829, caiF). Four (ycgW, yiaB, b0829, caiF) of these six microsatellite loci show statistically significant differences (P<0.05). It means that the analysis using four microsatellite loci including ycgW, yiaB, b0829, and caiF can confirm among the farms. Five E. coli samples in one farm have same SSR repetition at all markers. But, there are significant differences from other farms at Four (ycgW, yiaB, b0829, caiF) microsatellite loci. These results emphasize again that the four microsatellite loci makes a difference in the amplified DNA fragments, enabling it to be used for E. coli genotyping.

• Journal of Plant Biotechnology
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• v.44 no.3
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• pp.243-263
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• 2017

This study is to establish the varietal discrimination based on DNA profiling of different varieties of rice. We examined the genetic distance among Korean rice varieties using allele frequencies and a genetic diversity analysis with Simple Sequence Repeats (SSRs) markers. The analysis of the genetic diversity and genetic relationships of 243 Korean rice varieties was varied out using 20 SSRs markers. A total of 268 alleles were detected, ranging from 6 to 32, with an average of 13.45 alleles per locus, and and average of gene diversity (GD) of 0.556. Seven SSR markers were selected as key markers for discrimination among the Korean rice varieties. Concerning the results, 243 varieties (100%) were discriminated among by using acrylamide gel and fragment analyzer-based markers. In conclusion, this study provides useful basic data that can be utilized concerning Korean rice varieties breeding and development. In addition, we will have to manage and conserve as a valuable genetic resource, without losing the diversity of Korean rice varieties.