• Journal of Life Science
• /
• v.18 no.10
• /
• pp.1442-1446
• /
• 2008

Seven populations of 586 Hanwoo have been characterized by using 10 microsatellite DNA markers. Size of microsatellite markers decided using GeneMapper Software (v.4.0) after analyze in kinds of ABI machine of name of 3130. Frequencies of microsatellites markers were used to estimate heterozygosities and genetic distances. Genetic distancesbetween populations were obtained using Ne's DA distance method. Expected heterozygosity between each population was estimated very analogously. Genetic distances (0.0413) between Kangwan (KW) and Gyonggi (GG), Jeonpuk (JP) were nearest than distances between other populations by 0.021. Genetic distances between Gyonggi (GG) and Kyongpuk (KP) showed far distance than other populations by 0.032. In the UPGMA tree that is made based on DA distance matrix. Each individuals were not ramified to different group and were spread evenly in phylogenetic dendrogram about all Hanwoo of each regional area populations. But Hanwoo proven population was ramified to different group.

• Korean Journal of Poultry Science
• /
• v.35 no.4
• /
• pp.361-366
• /
• 2009

The purpose of this study was to assess the genetic variation and establish the relationship amongst breeds and strains using 7 chicken specific microsatellite markers. A total of 317 DNA samples from four Korean native chicken (KNC) strains (KR: Korean Native Red chicken strain, KY: Korean Native Yellow chicken strain, KL: Korean Native Black chicken strain, KO: Ogol chicken strain) and three introduced endemic chicken breeds (LE: Leghorn chicken breed, RI: Rhode Island Red chicken breed, CO: Cornish chicken breed). The size of microsatellite markers was decided using GeneMapper Software (v.4.0) after being analyzed using an ABI 3130 Genetic Analyzer. Frequencies of microsatellites markers were used to estimate heterozygosities and genetic distances. The lowest distance (0.074) was observed between the KY and KL breeds and the highest distance (0.779) between the KL and LE breeds. The KNC strains (KR, KY, KL) have comparatively near genetic distance each other. On the other side, each individual was not ramified to different groups and were spread evenly in phylogenetic dendrogram about all the KNC of each strain populations. But the endemic breed populations (LE, RI, CO) were ramified to different groups. The microsatellite polymorphism data were shown to be useful for assessing the genetic relationship between Korean native strains and other foreign breeds.

• Journal of Intelligence and Information Systems
• /
• v.17 no.1
• /
• pp.127-138
• /
• 2011

The core service of most research portal sites is providing relevant research papers to various researchers that match their research interests. This kind of service may only be effective and easy to use when a user can provide correct and concrete information about a paper such as the title, authors, and keywords. However, unfortunately, most users of this service are not acquainted with concrete bibliographic information. It implies that most users inevitably experience repeated trial and error attempts of keyword-based search. Especially, retrieving a relevant research paper is more difficult when a user is novice in the research domain and does not know appropriate keywords. In this case, a user should perform iterative searches as follows : i) perform an initial search with an arbitrary keyword, ii) acquire related keywords from the retrieved papers, and iii) perform another search again with the acquired keywords. This usage pattern implies that the level of service quality and user satisfaction of a portal site are strongly affected by the level of keyword management and searching mechanism. To overcome this kind of inefficiency, some leading research portal sites adopt the association rule mining-based keyword recommendation service that is similar to the product recommendation of online shopping malls. However, keyword recommendation only based on association analysis has limitation that it can show only a simple and direct relationship between two keywords. In other words, the association analysis itself is unable to present the complex relationships among many keywords in some adjacent research areas. To overcome this limitation, we propose the hybrid approach for establishing association network among keywords used in research papers. The keyword association network can be established by the following phases : i) a set of keywords specified in a certain paper are regarded as co-purchased items, ii) perform association analysis for the keywords and extract frequent patterns of keywords that satisfy predefined thresholds of confidence, support, and lift, and iii) schematize the frequent keyword patterns as a network to show the core keywords of each research area and connecting keywords among two or more research areas. To estimate the practical application of our approach, we performed a simple experiment with 600 keywords. The keywords are extracted from 131 research papers published in five prominent Korean journals in 2009. In the experiment, we used the SAS Enterprise Miner for association analysis and the R software for social network analysis. As the final outcome, we presented a network diagram and a cluster dendrogram for the keyword association network. We summarized the results in Section 4 of this paper. The main contribution of our proposed approach can be found in the following aspects : i) the keyword network can provide an initial roadmap of a research area to researchers who are novice in the domain, ii) a researcher can grasp the distribution of many keywords neighboring to a certain keyword, and iii) researchers can get some idea for converging different research areas by observing connecting keywords in the keyword association network. Further studies should include the following. First, the current version of our approach does not implement a standard meta-dictionary. For practical use, homonyms, synonyms, and multilingual problems should be resolved with a standard meta-dictionary. Additionally, more clear guidelines for clustering research areas and defining core and connecting keywords should be provided. Finally, intensive experiments not only on Korean research papers but also on international papers should be performed in further studies.

• Korean Journal of Microbiology
• /
• v.43 no.4
• /
• pp.256-263
• /
• 2007

We performed the biochemical characteristics, molecular epidemiologocal analysis, and drug susceptibility test on V. vulnificus isolated from environmental sources in Incheon. For this study, 233 strains were isolated from seawater, sediment, shellfish. V. vulnificus isolates were divided into 15 biochemical groups, which were positive for ONPG and Amygdalin test. Among the 209 strains, 206 (98.6%) strains and 110 (52.6%) strains revealed positive for vvhA and viuB gene, and the viuB gene detection rates of V. vulnificus from seawater, shellfish and sediment were 48%, 48.5% and 61.6%, respectively. From disc diffusion test on 175 isolates, most of strains were sensitive to Imipenem (100.0%), Sulfamethoxazole/trimethoprim (98.9%), Tetracycline, Ciprofloxacin (98.3%), Ampicillin/sulbactam (97.1%), Ohloramphenicol (96.6%), Cefepime (94.9%) and Ceftriaxone (94.8%), multi-drug resistance rates was 31.5% of seawater, 34.4% of sediment and 29.2% of shellfish. PFGE was performed on 233 V. vulnificus isolates with the objective of investigating the extent of genetic diversity of these isolates in our region. We could find that at least 126 different PFGE patterns were generated according by 90% of similarity and 13 clusters by 58% of similarity. The major cluster was type I (44.6%) during the most of the year, and type J was frequent pattern in June and October. There were 9 distinct PFGE types in July, 8 types in August, 7 types in June, 6 types in September, 5 types in October 3 types in May and 1 type in March.

• Korean Journal of Ichthyology
• /
• v.23 no.4
• /
• pp.288-299
• /
• 2011

Freshwater fish fauna and community structure were surveyed through 21 lakes in the Yeungnam area including Gyeongsangbukdo and Gyeongsangnamdo provinces, Korean Peninsula from April 2008 to October 2009. Among 21 lakes, 16 lakes belong to the Nakdong River and 5 are independent drainages. From the present study, 61 species (44 genera, 15 families) were collected including 32 cyprinid species (52.5%), 6 cobitid species (9.8%) and so on. The dominant and subdominant species in aspect of the number of individuals were Hypomesus nipponensis (26.6%) and Squalidus gracilis majimae (14.8%), respectively. On the other hand, in aspect of in biomass, dominant and subdominant species were Lepomis macrochirus (19.8%) and Cyprinus carpio (14.7%), respectively. Among 61 examined species, there were found 20 Korean endemic species and 2 Korean endangered species (Pseudobagrus brevicorpus and Pungitius kaibarae). P. brevicorpus was found in Yongyeonji and Yeongcheonho, and P. kaibarae in Yongyeonji. In addition, 5 exotic species were identified such as Cyprinus carpio nudus (leather carp), Carassius cuvieri, Hypophthalmichthys molitrix, Lepomis macrochirus and Micropterus salmoides. Interestingly, a bluegill L. machrochirus appeared dominant or subdominant species in 5 of 21 examined lakes. Five species introduced from the other rivers in Korean Peninsula were additionally described. In the present study, it was first reported that Micropercops swinhonis inhabits in the Nakdong river basin. The fish species diversity, evenness and dominant indices were examined, and a dendrogram based on similarity indices of inhabiting species among the 21 examined lakes was constructed and discussed.

• Korean Journal of Microbiology
• /
• v.35 no.3
• /
• pp.197-204
• /
• 1999

A total of 22 Leptospiua inlermgans field isolates from the ~ a t s captured in 5 provinces of Korea in 1996, and 6 antigenically closely related relerence serovars of lai, yeonchon, birkini. gem, mwogolo. and canicola were analysed. When the antigenic characteristics were analysed by reactivity with 7 monoclonal antibodies prepared with sh.ains belongng to serogroup Icterohaemorrhagiae. all 22 isolates showed the same reaction pattern with that of serovar lai. Large restriction fragment patterns obtained after cleavage of geno~nic DNAs with infrequently cuttimg restriction enzymes were analyzed by pulsed-field pel electrophoresis(PFGE). Identification of leptospira strains by PFGE with Nor I, Asc I or Iise I digests correlated with their antigenically typed serovars, silh a few exceptions. PFGE of isolates, except for JR89, digested wjth Nor I showed identical pattern w~th serovar lai, showing 13 Cragments between 940 kb and 63 kb. When PFGE pallerns of JR89 were compared with those of serovar lai, Not I digest showed additional two hands of 1000 kb and 460 kb, while Asc I digest showed 650 kb fragment and Fse I digest did not show the fragment of 280 kb. Whereas serovar yeonchon. which was isolated in Korea and identified as a new serovar previously. could be differentiated from serovar lai in antigenic reactivities with monoclonal antibodres. it showed the similar PFGE pattern with serovar lai includin~ reference and field isolates. It was suggested that Korean leptospiral field isolates are closely related in DNA level.

• Horticultural Science & Technology
• /
• v.31 no.6
• /
• pp.772-781
• /
• 2013

The objective of this study was to develop simple sequence repeat (SSR) markers from expressed sequence tags (EST) of lettuce (Lactuca sativa) and identify 9 germplasms from 3 wild species of lettuce and 61 commercial cultivars using the developed EST-SSR markers. A total of 81,330 lettuce ESTs from NCBI databases were used to search for SSR and 4,229 SSR loci were identified. The highest proportion (59.12%, 2500) was represented by trinucleotide, followed by dinucleotide (29.70%, 1256) and hexanucleotide (6.62%, 280) among SSR repeat motifs. Totally 474 EST-SSR primers were developed from EST and a random set of 267 primers was used to assess the genetic diversity among 9 germplasms and 61 cultivars. Out of 267 primers, 47 EST-SSR markers showed polymorphism between 7 cultivars. Twenty-six EST-SSR markers among 47 EST-SSR markers showed high polymorphism, reproducibility, and band clearance. The relationship between 26 markers genotypes and 70 accessions was analyzed. Totally 127 polymorphic amplified fragments were obtained by 26 EST-SSR markers and two to nine SSR alleles were detected for each locus with an average of 4.88 alleles per locus. Average polymorphism information content was 0.542, ranging from 0.269 to 0.768. Genetic distance of clusters ranged from 0.05 to 0.94 between 70 accessions and dendrogram at a similarity of 0.34 gave 7 main clusters. Analysis of genetic diversity revealed by these 26 EST-SSR markers showed that the 9 germplasms and 61 commercial cultivars were discriminated by marker genotypes. These newly developed EST-SSR markers will be useful for cultivar identification and distinctness, uniformity and stability test of lettuce.

• Korean Journal of Environmental Biology
• /
• v.26 no.2
• /
• pp.66-75
• /
• 2008

The level of genetic diversity and genetic relationships among Korean ring-necked pheasant (Phasianus colchicus karpowi) habitat and subspecies have been investigated based on Inter Simple Sequence Repeat (ISSR) markers. Wild and domesticated Korean ring-necked pheasant, hybrids between domesticated Korean ring-necked and foreign subspecies, and four foreign subspecies; Chinese ring-necked (P. c. torquatus), Melanistic mutant (P. c. mut. tenebrosus), XL White (P. c. mut) and Southern green (P. c. versicolor) were used for comparison. On the basis of the results of AMOV A, 94.08% of genetic diversity in Korean ring-necked was allocated among individuals within habitat differences. Estimate of $\Phi$st, which represents the degree of genetic differentiation among habitats was 5.9%. Based on the dendrogram reconstructed by UPGMA, Yangpyung habitat of the eight habitats turned out to be distinct from others habitat. Interestingly, domesticated Korean ring-necked and hybrid mixture showed closer genetic relationship with four foreign subspecies than Korean ring-necked. As a consequence of AMOVA, 96.63% of genetic diversity in four foreign subspecies was allocated among individuals within subspecies. Estimate of $\Phi$st representing the degree of genetic differentiation among subspecies was 3.4%, which was lower than that among habitats of Korean ring-necked. The lower level of genetic difference among four foreign subspecies showed that these subspecies were genetically closer even though they were morphologically classified into four different subspecies. When seven habitats of Korean ring-necked pheasant and four foreign subspecies were divided into Korean and Foreign Pheasant Groups, respectively, more than 17% of genetic diversity was allocated between groups (about 4% among habitats/subspecies within groups). This observation implied that Korean ring-necked pheasant is genetically quite different from four foreign subspecies. On the basis of cluster analysis, three foreign subspecies (Chinese ring-necked pheasant, Melanistic mutant pheasant, and XL White pheasant) formed a distinct group with domesticated Korean ring-necked pheasant and hybrid mixture at 98% confidence interval.

• The Korean Journal of Mycology
• /
• v.26 no.3 s.86
• /
• pp.373-379
• /
• 1998

Rhizoctonia solani [Thanatephorus cucumeris (frank) Donk], one of the major soil-borne plant pathogens with world-wide distribution, can cause great damages on various crops. In Korea, sheath blight on rice caused by this pathogen is the major concern, and active studies on this pathogen have been performed. However, most of these studies were concerned with pathogenicity of the isolates instead of molecular analyses of different AGs of R. solani. Therefore, in this study, thirty isolates of Rhizoctonia solani collected from various sources were used for the analyses of genetic relationships among themselves and for the rapid anastomosis grouping with RAPD method. As a result, thirty isolates of known and unknown AGs were grouped into five subgroups and each group included AG-1, AG-2, AG-3, AG-4, and AG-5. RS-1 isolate was found to be closely related to AG-5. Isolates RS-4, RS-14, RS-17, and RS-16 were found to be closely related to AG-2-2(III B). Isolate RS-13 was closely related to AG-4, isolates RS-8 and RS-10 were closely related to AG-1(I B), and isolates RS-7 and RS-21 were closely related to AG-2-2(IV). Isolate RS-19 was closely related to AG-1(I C), and isolates RS-3, RS-5, RS-18, RS-6, and RS-15 were found to be closely related to AG-1.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.23 no.1
• /
• pp.89-104
• /
• 2021

Based on the TF-IDF weighted value that evaluates the importance of words that play a key role, the semantic network analysis(SNA) was conducted on the self-introduction letter of freshman at Korea National College of Agriculture and Fisheries(KNCAF) in 2020. The top three words calculated by TF-IDF weights were agriculture, mathematics, study (Q. 1), clubs, plants, friends (Q. 2), friends, clubs, opinions, (Q. 3), mushrooms, insects, and fathers (Q. 4). In the relationship between words, the words with high betweenness centrality are reason, high school, attending (Q. 1), garbage, high school, school (Q. 2), importance, misunderstanding, completion (Q.3), processing, feed, and farmhouse (Q. 4). The words with high degree centrality are high school, inquiry, grades (Q. 1), garbage, cleanup, class time (Q. 2), opinion, meetings, volunteer activities (Q.3), processing, space, and practice (Q. 4). The combination of words with high frequency of simultaneous appearances, that is, high correlation, appeared as 'certification - acquisition', 'problem - solution', 'science - life', and 'misunderstanding - concession'. In cluster analysis, the number of clusters obtained by the height of cluster dendrogram was 2(Q.1), 4(Q.2, 4) and 5(Q. 3). At this time, the cohesion in Cluster was high and the heterogeneity between Clusters was clearly shown.