• Journal of Korean Society of Forest Science
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• v.90 no.2
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• pp.169-175
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• 2001

Genomic DNAs were extracted from the leaves of 182 ginkgo trees (Ginkgo biloba L.) planted in 6 regions and subjected to the analysis of both I-SSR and RAPD markers. A total of 227 amplicon variants were generated by PCR using 15 I-SSR primers and 67 amplicons by PCR with 5 RAPD primers. Levels of genetic diversity within 6 populations were turned out to be similar (Shannon's Index, I-SSR : 0.35~0.40; mean of 0.38, RAPD : 0.31~0.38; mean of 0.35, combined : 0.35~0.40; mean of 0.37). Ranks of the level of genetic diversity estimated from I-SSR, RAPD, and combined data were not coincided each other. Majority of genetic diversity was allocated among individuals within populations (I-SSR : 94.31%, RAPD : 93.62%, combined : 93.57%), which resulted in pretty low level of population differentiation. Genetic differentiation between male and female groups was turned out to be quite low (I-SSR : 0.03, RAPD : 0.091, combined : 0.043), which slightly fluctuated when analysis was restricted to the data obtained from 3 regions where both male and female trees were sampled (I-SSR : 0.038, RAPD : 0.084, combined : 0.047). Genetic relationships among the populations, reconstructed by UPGMA, were not coincided with geographic affinity, which might be resulted from sharing of seed sources in some regions. Whereas independent cluster analyses with I-SSR data and RAPD data, respectively, reclassified by sexes revealed two sexual groups in which all the male and the female populations were clustered together, cluster analysis with combined data did not show clear sexual grouping.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.1
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• pp.81-88
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• 2007

The evaluation of soybean germplasm has mainly been carried out by morphological characters at Genetic Resources Division, Rural Development Administration (RDA). However, this information has been limited serving a diverse information for user and effectively managing the soybean germplasm. To resolve this problem, soybean collection conserved at RDA gene bank was profiled using nine soybean SSR (Simple Sequence Repeat) markers. Soybean SSR allele was confirmed using genescan and genotyper softwares of automatic sequencer for accurate genotyping of each accession and continuous accumulation of data. SSR profiling of soybean germplasm has been carried out from 2,855 (Satt458) to 4,368 (Satt197) accessions by locus. The number of allele revealed 267 with an average of 29.6 in total accession, and varied from a low of 21 (Satt532 and Satt141) to a high of 58 (Sat_074). Although the number of accessions of wild soybean is less than that of soybean landraces, Korean wild soybean is more variable than other soybean landraces populations in total number of alleles. However, Korean soybean landraces were more variable than Korean wild soybeans in 5 loci. In the allele frequency, wild soybean accessions showed an even distribution in all alleles and higher distribution in low ladder than in high ladder. Also, Korean soybean landraces revealed a high condensed frequency in Satt286 (202 bp, 232 bp), Chinese soybean landraces in Satt197 (171 bp) and Satt458 (173 bp), and Japanese soybean landraces in Sat_074 (244 bp) and Satt458 (170 bp). These SSR profile information will be provided as indications of redundancies or omissions of accessions and can aid in managing soybean collection held at RDA gene bank. The information on diversity analysis could help to enlarge the genetic diversity of materials in breeding program, and could be used to develop a core collection of soybean germplasm.

• Korean Journal of Head & Neck Oncology
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• v.17 no.2
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• pp.162-168
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• 2001

Background: Inverted papilloma(IP) of the nasal cavity and paranasal sinuses is a benign neoplastic condition that can be associated with squamous cell carcinoma (SCC). Several studies have indicated an etiologic role for viruses in the development of inverted papilloma. And it is necessary to find out the significance of a biologic markers such as p53, c-erbB-2 to predict the malignant potential. The purposes of this study are to detect HPV in inverted papilloma of the nasal cavity and paranasal sinus, to examine role of HPV as an etiological agent, to examine the relationship between HPV subtype and malignant transformation of inverted papilloma, and to investigate the relation between expression rate of p53, c-erbB-2 and HPV in recurrent or malignant transformation cases. Material and Methods: Thirty two cases of inverted papilloma(IP) in the nasal cavity and paranasal sinuses were reviewed and classified into 3 groups; simple IP, IP with dysplasia group, IP with squamous cell carcinoma group. Paraffin embedded achival tissue was used in this study. The HPV was detected by in situ hybridzation (ISH) using HPV type 6/11, 16/18, 31/33/35 DNA probes. Expression of p53 and c-erbB-2 was examined by immunohistochemical staining. Results: 1) The HPV was detected in 6(19%) out of 32 cases. 2) The HPV 6/11 was dectected in 4 out of 21 cases of simple IP, HPV 16/18 in 1, HPV 31/33/35 in lout of 8 cases of IP with dysplasia respectively. 3) The positive expression of p53 was 13 cases out of 32 cases; 2 out of 21 cases of simple IP, all of 8 cases of IP with dysplasia and 3 cases of IP with squamous cell carcinoma 4) The positive expression of c-erbB-2 was in 24 out of 32 cases; 16 out of 21 cases of simple IP, 6 out of 8 cases of IP with dysplasia, 2 out of 3 cases of IP with squamous cell ca. 5) The recurrence of IP occurred in lout of 6 cases of positive for HPV, in 4 out of 26 cases negative for HPV. 6) The recurrence of IP occurred only in positive cases for p53. 7) The recurrence of IP occurred in 4(17%) out of 24 cases positive for c-erbB-2, in 1(13%) out of 8 cases negative for c-erbB-2. Conclusion: The p53 expression was associated with Inverted papillomas exhibiting evidence of malignant transformation. Also, there was a correlation between the p53 expression and recurrence.

• Journal of Plant Biotechnology
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• v.33 no.4
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• pp.309-313
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• 2006

Discovery of single nucleotide polymorphisms (SNPs), including small insertions and deletions, is one of the hot topics in genetic research. The most common type of sequence variant consists of single base differences or small insertions and deletions at specific nucleotide positions. Significance of SNPs in rice is increasing for genetic research, positional cloning and molecular breeding. $F_2$ 170 lines and $F_3$ 194 lines derived from Sangjuchalbyeo/HR13721-53-3-1-3-3-2-2 Were used for Searching SNP markers related to bacterial blight resistance. Sangjuchalbyeo is susceptible to bacterial blight, but HR13721-53-3-1-3-3-2-2 has Xa1 gene resistant to bacterial blight. Individual lines were inoculated with $K_1$ race of bacterial blight and resistant or susceptible was evaluated after 3 weeks from inoculation. The genotypes of population were analysed by PCR-RFLP for SNP marker developing. The segregation of $F_2\;and\;F_3$ population showed almost 3:1, 1:1 ratio, respectively. Analysis of genotype using SNP marker is capable of confirming resistance for $K_1$ race and genotype through amplifying the gene using 16PFXal primer and digested the PCR product with Eco RV. There were close relation between resistance test for $K_1$ race and SNP marker genotype. Especially, DNA analysis using SNP marker is capable of judging homozygote/heterozygote in $F_2$ population compared with resistant test for Kl race. So, it seems to improve the selection efficiency in disease resistant breeding.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.448-457
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• 2015

Developing rice lines with various amylose contents is necessary to diverse usages of rice in terms of raw materials for processed food production, and thereby to promote rice consumption in Korea. A rice mutant line, 'Namil(SA)-dull1' was established through sodium azide mutagenesis on 'Namil', a non-glutinous Korean Japonica rice cultivar. Namil(SA)-dull1' had dull endosperm characteristics and the evaluated amylose content was 12.2%. A total of 94 F2 progenies from a cross between 'Namil(SA)-dull1' and 'Milyang23', a non-glutinous Tongil-type rice cultivar, was used for genetic studies on the endosperm amylose content. Association analyses, between marker genotypes of 53 SSR anchor markers and evaluated amylose contents of each 94 F2:3 seeds, initially localized rice chromosome 6 as the harboring place for the modified allele(s) directing low amylose content of 'Namil(SA)-dull1'. By increasing SSR marker density on the putative chromosomal region followed by association analyses, the target region was narrowed down 0.94 Mbp segment, expanding from 28.95 Mbp to 29.89 Mbp, on rice chromosome 6 pseudomolecule. Among the SSR loci, RM7555 explained 84.2% of total variation of amylose contents in the $F_2$ population. Further physical mapping on the target region directing low amylose content of 'Namil(SA)-dull1' would increase the breeding efficiency in developing promising rice cultivars with various endosperm characteristics.

• Journal of Gastric Cancer
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• v.8 no.4
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• pp.169-175
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• 2008

Purpose: The main target of 5-fluorouracil (5-FU) is thymidylate synthase (TS). A high TS expression has been identified as promoting resistance to 5-FU. For colorectal cancers, the response to 5-FU based adjuvant chemotherapy is different according to the microsatellite instability (MSI) status. The reports on the relationship between MSI and the TS expression in colorectal cancer have been inconsistent. No data is available for gastric cancer regarding the relationship between MSI and the TS expression. Therefore, we studied the relationship between MSI and the TS expression in gastric cancer. Materials and Methods: Ninety-nine consecutive patients who underwent radical gastrectomy for gastric cancer from January 2004 to May 2006 at Bundang CHA hospital were studied. MSI was assessed for five markers (BAT25, BAT26, D2S123, D5S346, and D17S250) by PCR and with using an ABI prism 3100 Genetic analyzer. The TS expression was analyzed by immunohistochemistry with using mouse anti-thymidylate synthase monoclonal antibody to the TS 106 clone. Results: Out of the ninety-nine patients, MSS/MSI-L was detected in 92 (92.1%) cases and 7 cases (7.1%) were MSI-H. A negative TS expression was found in 46 (46.5%) cases, a low TS expression was found in 33 (33.3%) and a high TS expression was found in 20 (20.2%). Out of 92 MSS/MSI-L patients, the number of patients with negative, low and high TS expressions were 46 (50%), 30 (32.6%) and 16 (17.4%), respectively. Out of the 7 MSI-H patients, the number of patients with negative, low and high TS expressions were 0 (0%), 3 (42.9%) and 4 (57.1%), respectively. The relationship between MSI-H and a high TS expression was statistically significant. Conclusion: Gastric cancer with MSI-H showed higher levels of a TS expression compared to the gastric cancer with MSS/MSI-L.

• Korean Journal of Plant Taxonomy
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• v.48 no.4
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• pp.249-259
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• 2018

$Iso{\ddot{e}}tes$ L. ($Iso{\ddot{e}}taceae$) is a cosmopolitan genus of heterosporous lycopods containing ca. 200 species being found in lakes, streams, and wetlands of terrestrial habitats. Despite its ancient origin, worldwide distribution, and adaptation to diverse environment, species in $Iso{\ddot{e}}tes$ show remarkable morphological simplicity and convergence. Allopolyploidy appears to be a significant speciation process in the genus. These characteristics have made it difficult to assess the phylogenetic relationships and biogeographic history of $Iso{\ddot{e}}tes$ species. In recent years, these difficulties have somewhat been reduced by employing multiple molecular markers. Here, we reconstruct the phylogenetic relationships in East Asian $Iso{\ddot{e}}tes$ species. We also provide their divergence time and biogeographic origin using a fossil calibrated chronogram. East Asian $Iso{\ddot{e}}tes$ species are divided into two clades: I. asiatica and the remaining species. $Iso{\ddot{e}}tes$ asiatica from Hokkaido forms a clade with northeastern Russian and western North American $Iso{\ddot{e}}tes$ species. In clade I, western North America is the source area for the dispersal of $Iso{\ddot{e}}tes$ to Hokkaido and northeastern Russia via the Bering land bridge during the late Miocene. The remaining $Iso{\ddot{e}}tes$ species (I. sinensis, I. yunguiensis, I. hypsophila, I. orientalis, I. japonica, I. coreana, I. taiwanensis, I. jejuensis, I. hallasanensis) from East Asia form a sister group to Papua New Guinean and Australian species. The biogeographic reconstruction suggests an Australian origin for the East Asian species that arose through long-distance dispersal during the late Oligocene.

• Korean Journal of Breeding Science
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• v.51 no.3
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• pp.263-276
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• 2019

'Sinjinbaek' is a bacterial blight (BB)-resistant, mid-late maturing rice cultivar with high grain quality. To diversify the resistance genes and enhance the resistance of Korean rice cultivars against BB, 'Sinjinbaek' was developed from a cross between 'Iksan493' (cultivar name 'Jinbaek') and the F₁ cross between 'Hopum' and 'HR24670-9-2-1' ('HR24670'). 'Jinbaek' is a BB-resistant cultivar with two BB resistance genes, Xa3 and xa5. 'Hopum' is a high grain quality cultivar with the Xa3 resistance gene. 'HR24670' is a near-isogenic line that carries the Xa21 gene, a resistance gene inherited from a wild rice species O. longistaminata, in the genetic background of japonica elite rice line 'Suweon345'. 'Sinjinbaek' was selected through the pedigree method, yield trials, and local adaptability tests. Using bioassay for BB races and DNA markers for resistance genes, three resistance genes, Xa3, xa5, and Xa21, were pyramided in the 'Sinjinbaek' cultivar. 'Sinjinbaek' exhibited high-level and broad-spectrum resistance against BB, including the K3a race, the most virulent race in Korea. 'Sinjinbaek' is a mid-late maturing rice cultivar tolerant to lodging. It has multiple disease resistance against BB, rice blast, and stripe virus. The yield of 'Sinjinbaek' was similar to that of 'Nampyeong'. 'Sinjinbaek' showed excellent grain appearance, good taste of cooked rice, and enhanced milling performance, and we concluded that it could contribute to improving the quality of BB-resistant cultivars. 'Sinjinbaek' was successfully introgressed with the Xa21 gene without the linkage drag negatively affecting its agronomic characteristics. 'Sinjinbaek' improved the resistance of Korean rice cultivars against BB by introgression of a new resistance gene, Xa21, as well as by pyramiding three resistance genes, Xa3, xa5, and Xa21. 'Sinjinbaek' would be suitable for the cultivation in BB-prone areas since it has been used in breeding programs for enhancing plants' resistance to BB (Registration No. 7273).