• Journal of Life Science
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• v.23 no.7
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• pp.847-853
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• 2013

The genus Hemerocallis (family Xanthorthoeaceae) is a herbaceous species, some of which are very important in herbal medicines. We evaluated the rps16-trnK region of the chloroplast DNA of a representative sample of eight taxa in Korea to estimate phylogenetic relationships within the taxa of this genus. Due to differences in the number of inserted nucleotides, the aligned data for Hemerocallis ranged from 729 (H. aurantiaca) to 742 nucleotides (H. fulva var. kwanso), with a mean of 736. Although several small indels and 20 inserts were present, sequence variation within the Hemerocallis genus was mostly due to nucleotide substitutions. All rps16-trnK trees generated in Korea exhibited a well-solved topology, with high bootstrap support, irrespective of the methods (parsimony) and the setting used. The node of H. minor and H. littorea was strongly supported, with a high bootstrap value in three trees, and these two taxa were sistered with H. thunbergii. The number of chromosomes was not congruent with that found in a previous study with RAPD, but the number was in agreement with the results of this study.

• Journal of Life Science
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• v.23 no.11
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• pp.1305-1310
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• 2013

Dill (Anethum graveolens L.) is an annual herb with a long history and it is mainly used as a spice and as a medicine that is effective as a digestive aid, a sedative, and a narcotic, and that helps remove bad breath. Dill grows wild in the districts along the shores of the Mediterranean Sea, West Asia, China, and Korea. An estimate of the phylogenetic relationships within dill accessions in 20 countries was inferred using data from the rps16-trnK3-intergenic spacer. The aligned data sets for dill ranged from 747 to 779 nucleotides (bp) as a result of the differences in the insert/delete nucleotides. The sequence variation within the dill accessions was mostly due to nucleotide substitutions, although several small insertions and deletions can be found. Among 100 accessions from 20 countries, the Eastern Asia accessions were more closely related to the North American accessions than to the Central Asia and European accessions. Although some accessions were not congruent completely with geographical locations, the dill accessions with rps16-trnK analysis resulted in plants with better-resolved clades.

• Molecules and Cells
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• v.27 no.4
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• pp.459-465
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• 2009

MUG1 is a MULE transposon-related domesticated gene in plants. We assessed the sequence diversity, neutrality, expression, and phylogenetics of the MUG1 gene among Oryza ssp. We found MUG1 expression in all tissues analyzed, with different levels in O. sativa. There were 408 variation sites in the 3886 bp of MUG1 locus. The nucleotide diversity of the MUG1 was higher than functionally known genes in rice. The nucleotide diversity (${\pi}$) in the domains was lower than the average nucleotide diversity in whole coding region. The ${\pi}$ values in nonsynonymous sites were lower than those of synonymous sites. Tajima D and Fu and Li $D^*$ values were mostly negative values, suggesting purifying selection in MUG1 sequences of Oryza ssp. Genome-specific variation and phylogenetic analyses show a general grouping of MUG1 sequences congruent with Oryza ssp. biogeography; however, our MUG1 phylogenetic results, in combination with separate B and D genome studies, might suggest an early divergence of the Oryza ssp. by continental drift of Gondwanaland. O. long-istaminata MUG1 divergence from other AA diploids suggests that it might not be a direct ancestor of the African rice species.

• Composites Research
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• v.19 no.2
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• pp.13-19
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• 2006

In this paper, parametric study was carried out to design sandwich structures for EDM machines controlling stacking sequence, stacking thickness of composites and rib configuration. Sandwich structures which are dealt with in this paper are composed of fibre reinforced composite for skin material and foam or resin concrete for core materials. The sandwich column has cruciform rib to enhance bending stiffness of the structure and the bed has several vertical ribs to resist the normal forces and vibration. The design parameters such as rib thickness and stacking sequence were controlled to enhance the system robustness. Finite element analysis was also carried out to verify the variation of static and dynamic stiffness of the structures according to the variation of the parameters. Vibration tests were performed to verify the natural frequencies and damping ratios of the manufactured composite structures. The appropriate shape and configuration conditions for micro-EDM machine structures are proposed.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.259-259
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• 2022

Soil salinity is a major factor that reduces crop yields. The amount of soil affected by salinity is about 83 million hectares (FAO 2000), which is increasing due to the effects of climate change. In soybean [Glycine max (L.) Merr.], nutritional properties such as protein, starch, and sucrose content together with biomass and yield tends to reduce due to excessive salt. As a result of QTL mapping using the 169 F_2:3 population from the KA-1285 (salt-tolerant) × Daepung (salt-sensitive) in a previous study, two major QTLs (Gm03_39796778 and Gm03_40600088) related to salt tolerance were found on chromosome 3. In this study, the CDS region of the Gmsalt3 gene was analyzed using the ABI 3730x1 DNA Analyzer (Macrogen, Korea). The sequence of Gmsalt3 gene in KA-1285 was compared with Williams 82.a4.vl and PI483463 (Glycine soja). Two transversions were found at exon6 in KA-1285 and PI483463. Currently, whole genome sequencing and variation analysis using the Illumine Novaseq 6000 machine (Illumina, USA) are in progress. The results of this study can provide useful molecular markers for the selection of salt-tolerant soybeans and can be used as basic data for future salt-tolerant gene research.

• Korean journal of applied entomology
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• v.37 no.1
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• pp.23-30
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• 1998

Restriction fragment length polymorphism (RFLP) of a DNA has been a useful tool for analyzing genetic variation. This research was performed to establish an RFLP analytic method on the mitochondrial DNA (mtDNA) of the beet armyworm, Spodoptera exigua (Hiibner). To do this, total size of the mtDNA was measured and polymerase chain reaction (PCR) primers were selected. Its mitochondrial genome size was ca. 16kb. From a serial PCR test of 29 primers refered to the compilation of Simon et al. (1994), 22 primers were selected to amplify its mtDNA fragments. These primers resulted in short (300-700 bp) or long (1000-2000 bp) DNA products which represented a total or partial sequence of each of CO-I, CO-11, Cyt-B, ND-1, 12s rRNA, 16s rRNA, and some tRNAs. PCR-RFLP was performed in some variable mtDNA regions with 8 kinds of 4bp recognizing restriction enzymes. Different populations from Andong, Kyungsan, and Sunchun did not show any restriction site polymorphisms but had some length variation in certain regions of mtDNA.

• Research in Plant Disease
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• v.24 no.2
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• pp.170-173
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• 2018

Three isolates of Cucumber mosaic virus isolated from Commelina communis plants showing chlorosis and mosaic were collected in Chungju and Chuncheon, Korea. To confirm genetic variation of these three isolates (CMV-Co, CMV-Co2, and CMV-Co3), we performed PCR-RFLP and sequence analysis. Sequences of coat protein genes of CMV-C0, -Co2 and -Co3 were compared with CMV-Fny and showed 96.3%, 96.3%, and 95.9% similarities, respectively. In host reactions, three CMV-Co isolates induced systemic necrosis in Cucurbita pepo unlike CMV-Fny and CMV-Co, CMV-Co2 and CMV-Co3 observed differential symptoms responses in Physalis angulata and Nicotiana rustica. These results indicated that three isolates of CMV isolated from C. communis have genetic and biological variation.

• Korean Journal of Plant Resources
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• v.19 no.1
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• pp.189-195
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• 2006

We investigated the genetic variation in Stewartia koreana Nakai by examining 61 I-SSR amplicons in 120 individuals distributed among six natural populations in Korea. The overall percentage of polymorphic I-SSR amplicons was 81.9% and mean number of amplicons per I-SSR primer was 12.2. Levels of genetic diversity within 6 populations were similar each other[Shannon's Index $0.358{\sim}0.467$(mean: 0.407)]. The Mt. Obong population had the highest level of genetic diversity and was most distinctive from the other populations. Most variation existed among individuals within population(88.2%). Genetic differentiation among populations(${\phi}_{ST}$) was 0.118. The UPGMA dendrogram based on the genetic distance failed in showing decisive geographic relationships.

• Journal of the korean society of oceanography
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• v.33 no.3
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• pp.71-79
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• 1998

Silty tidal rhythmites were found from the upper Pleistocene sequence unconformably overlain by the Holocene tidal deposits within the macrotidal coastal zone of Youngjong Island, western coast of Korea. The rhythmites occur as vertically accreted, parallel and planar laminae that are 0.1-2.5 mm in thickness. Each lamina grades from coarse silt (mean grain size: 5-6.5 ${\phi}$) at the lower part into fine silt to mud (mean grain size: 6-7.5 ${\phi}$) at the upper part. The rhythmites can be classified into two types based on the patterns in laminar thickness variation. Type I is a bundle of 12-20 laminae in which laminar thickness varies sinusoidally. Type ll is an alternation of thick and thin laminae as a couplet. Type I is inferred as a product of varying tidal energy during a semimonthly (neap-spring) tidal cycle, in which thicker laminae were deposited during spring tides and thinner laminae were formed during neap tides. Type ll is interpreted to have been formed by asymmetric semidiurnal tidal currents in association with diurnal inequality, whereby thick lamina of each couplet represents dominant tidal current and the thin lamina reflects subordinate tidal current.

• 보존과학연구
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• s.25
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• pp.47-74
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• 2004

We investigated the nucleotide substitution and insertion polymorphism of the hypervariable region Ⅰ and Ⅱ in mt DNA by sequencing ancient DNA from 51 ancient bones and teeth excavated at Nuk-do and Yimdang-dong in Korea. It revealed 35 sequence types from the ancient Korean. Of these, different sequences were 34 sequences. There were 19 and 38 base substitutions in HVI and HVⅡ, respectively. Some substitutions were characteristic of East Asian populations as compared with data reported on Caucacianpopulations,16051, 16150, 16172, 16223 in region I and 73, 263 in region II were noted as polymorphic sites, respectively. These were distributed evenly along the control region, though the frequency of each site was variable. Nucleotide substitution rather than insertion and deletion was the prevalent pattern of variation. Insertion of cytosine between312 and 315 in region HVⅡ were detected up to 98% in 51 ancient bone samples. This sequence data represents a phylogenetic tree using NTI DNA Suite computer program. The phylogenetic tree showed that mt DNA sequences of Nuk-do bones were relative to west Siberian and Indonesian. The usefulness of mt DNA sequencing in ancient Korean population excavated atarchaeological sites is based on biological and historical evidence for origin and migration of ancient Korean.