• Korean Journal of Plant Tissue Culture
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• v.27 no.5
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• pp.359-366
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• 2000

Epigenetics represents a chromatin-mediated transcriptional repression which plays a control role in both animal and plant development. A number of different mechanisms have been described to be involved in the formation of chromatin structure: especially DNA methylation, nucleosomal histone modification, DNA replication timing, and binding of chromatin remodelling proteins. Epigenetic phenomena include genomic imprinting, dosage compensation of X-chromosome linked genes, mutual allelic interactions, paramutation, transvection, silencing of invasive DNA sequences, etc. They are often unstable and inherited in a non-Mendelian way. A number of epigenetic defects has been preferentially described in floral development. Here, epigenetic phenomena in model angiosperm plants and their corresponding mechanisms are reviewed.

• Journal of Sericultural and Entomological Science
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• v.42 no.2
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• pp.67-72
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• 2000

Autotetraploid 'Sawonppong 26'was induced by dropping clochicine solution in growing point of Keomseolppong which is of high rootability and some agronomic charactelistics are as follows. Sawonppong 26 is a tetraploid of Keomseolppong with 56 of the chromosome number. Its fertlization percent was 59.4% and the germination percent of sank seed was normal. Sugar degree of mulberry fruit was 13.3% and total acidity was 0.69%. Single fruit weight of Sawonppong 26 was increased by 79%, as compared to that of Keomseolppong. Even though percent of survival of hard wood cutting was 94%, number of rootings was less and diameter of root was slender, it is expectedly a promising variety to be used for a breeding parent from the aspect of rootability.

• Journal of Plant Biology
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• v.36 no.1
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• pp.75-81
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• 1993

Ginseng (Panax ginseng C.A. Meyer) hairy root transformed with Agrobacterium rhizogenes (strain A4) was examined cytogenetically and histologically to assess its characteristics. The optimum growth of hairy root obtained in hormone-free MS medium (sucrose 30 g/L, pH5-6) for long period cultures. All hairy root strains (HB1, HB2, HB3) had the 2n diploid number (2n=48) of chromosomes in root tip cells. There were no alteration in chromosome structure except in one cell of HB3 strain. Results of SDS-PAGE showed a few difference in pattern and number of bands between normal and hairy root of ginseng. The root anatomy of normal root and hairy root differed each other. The hairy root had a clearly defined vascular strand, and the morphology of cortical cells were disorganised with large intercellular spaces.

• The Korean Journal of Zoology
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• v.33 no.2
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• pp.217-221
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• 1990

The chromosomal analyses of Dendmcopos major hondoensis and D. leucotos Ieucotos(Picidae:Piciformes) in Korea were performed by conventional Giemsa staining and C-banding method. The diploid number of two species was 2n=90-92 and arm number was AN= 92-96.The conventional karyotypes were very similiar but distribution of constitutive heterochromatin were differ in the first chromosome. The second and several pairs of macro-telocentric chromosbmes have telomeric constitutive heterochromatin.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.459-462
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• 2004

This paper proposes a genetically inspired adaptive clustering algorithm. The algorithm automatically discovers the actual number of clusters and efficiently performs clustering without unduly compromising cluster purity. Chromosome encoding that ensures the correct number of clusters and cluster purity is discussed. The required fitness function is desisted on the basis of modified similarity criteria and genetic operators. These are incorporated into the proposed adaptive clustering algorithm. Experimental results show the efficiency of the clustering algorithm on synthetic data sets and real world data sets.

• Animal Systematics, Evolution and Diversity
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• v.8 no.2
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• pp.177-182
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• 1992

A ricefish Oryzias latipes sinesis Chen et al. of the family Oryzidae is recorded for the first time from western Korea. The present speciment are similar to O. l. latipes in most morphometric characters, but agree well with the original description of O. l. sinensin based on the diploid chromosome number of 46 with two large metacentric chromosomes and the lesser vertebrae number.

• The Korean Journal of Zoology
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• v.13 no.2
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• pp.35-43
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• 1970

사람은 물론 모든 생물의 體細胞는 여러 타입의 染色體를 이중으로 지니고 있어서 倍數(diploid number)라하고 生殖細胞는 그의 한쪽만을 갖어서 半數(haploid number)라 한다. 1956년에 이르기까지도 사람의 染色體의 倍數는 48로 알려지고 性染色體 구성은 확실하지 못한 상태에 있었다. 1956년 이래 體細胞 染色體 硏究에 관한 기술 방법의 비약적인 발전으로 인하여 사람의 정상인 核型은 물론 異常形質을 나타내는 個體의 染色體에 관해서도 정확한 데타를 얻을 수 있게 되었다. 染色體硏究에 있어 개선된 기술방벙의 가장 큰 것은 組織培養의 도입이다. 종래의 切片作成法(section method)을 지양하고, 사람 몸에서 지극히 적은 분량의 組織을 얻어가지고 生體에서와 거의 비슷한 환경을 주어 인공적으로 단층의 細胞를 이루어 증식시키는 방법이다. 1956년 사람의 染色體를 정확히 파악하여 倍數로 46개이며, 남자는 XY, 여자는 XX 의 性染色體를 지닌다는 점을 밝힌 Tjio 및 Levan도 사람의 胎兒의 肺組織을 培養한 것을 재료로 삼았던 것이다.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.22-22
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• 2001

To produce reconstituted rabbit embryos with fetal fibroblasts, the present study was evaluated the efficiencies of the different fusion and activation conditions as assessments of subsequent development and chromosome in the embryos. New Zealand White rabbits were used throughout the study. Fetal fibroblasts collected from 22-d of fetuses were cultured in DMEM ＋ 10% FBS in 5% $CO_2$ in air. The culture was maintained for 10 passages. In every passage half of cell suspension were kept In frozen. From rabbits treated with FSH in 30% PVP solution and hCG, oocytes were surgically collected from oviducts at 14 h post-hCG injection and stripped off their cumulus cells by re-pipetting in a 300 IU hyaluronidase solution. Oocytes with an extruded first polar body and dense cytoplasm were enucleated by micromanipulation in Ham's F-10 medium＋7.5 g/$m\ell$ cytochalasin B. Euncleation was confirmed under a fluorescence microscope after staining with 5 g/$m\ell$ bisbenzimide for 2 min. Each enucleated oocyte was injected with a fetal fibroblast into a perivitelline space. Reconstructed eggs were compared fusion rates either at 2.0 ㎸/cm or 1.6 ㎸/cm(60 sec, double pulses). After fusion, all eggs were activated with the combination of 5 M ionomycin (5 min) and 10 g/$m\ell$ cycloheximide (CHX, 3h), and cultured in CRlaa medium and transferred into TCM199＋10% FBS on day 3. Although there was not significantly differ in fusion rate between treatments (60%, 2.0 ㎸/cm vs. 79.4%, 1.6 ㎸/cm), none of them in the eggs fused with 2.0 ㎸/cm developed to blastocyst. In comparison of development and chromosome status between different activation treatments (Group 1; 5 M ionomycin/10 g/$m\ell$ CHX, Group 2; 5 M ionomycin/5 g/$m\ell$ CHX ＋ 2 mM DMAP after fusion with 1.6 ㎸/cm), there were not differ in cleavage and development rates (67.3% and 28.9% in Group 1; 67% and 33% in Group 2). All out of 8 embryos evaluated in Group 1 appeared a normal diploid chromosome sets and mean number of cells (Mean SEM) on day 4.5 of culture was 141.5 23.15 (n=8). It can be concluded that the use of cycloheximide has not happened in chromosome abnormalities, and fetal fibroblasts can be used for cloning in rabbit.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.3
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• pp.287-292
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• 1998

The objective of this study was to confirm whether the vitrification method using EFS35 has detrimental effect for cytoskeleton and chromosome constitution of the mouse oocytes by indirect immunocytochemistry and chromosome analysis. Mouse oocytes were vitrified using EFS35 which consisted of 35% ethylene glycol, 18% ficoll, 0.3 M sucrose and 10% FBS in M2 medium. The results obtained in this experiment were summarized as follows: When the survival rates after being exposed or vitrified in EFS35 were examined, there were not different between two groups (97.7 and 89.3%). Also, when the microtubule morphology and microfilament distribution in vitrified oocytes were examined, normal percentage of two cytoskeleton in vitrified group (95.5 and 100%) was not different from that in control (97.5 and 100%) and exposed group (92.3 and 100%). In addition, the rate of oocytes containing a normal chromosome number in vitrified group (73.5%) after IVF was not different from that in control (79.5%) and exposed group (78.7%). These results indicated that the cytoskeletal morphology and chromosome constitution of mouse oocytes were not affected by cryoprotectant (EFS35) or freezing apd that vitrification methods using EFS35 was suitable for cryopreservation of mouse oocytes.

• Korean Journal of Plant Resources
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• v.19 no.2
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• pp.323-330
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• 2006

The morphology and somatic chromosome numbers of Korean Parasenecio were investigated to estimate their taxonomic values. Some morphological characters, such as the length of whole plants, the numbers of cauline leaves, the shapes of leaf and petioles, the numbers of involucral bracts, floret numbers per head, presence of trichomes on the style, ratio between wide part and narrow part of floret and the size of achene were found to be a good characters for delimiting each taxa. Based upon these characters, six taxa, Parasenecio auriculala var. auriculata, P. auriculata var. kamtschatica, P. hastata subsp. orientalis, P. koraiensis, P. firmus, P. pseudotaimingasa, were recognized about their distribution in Korea, but 2 taxa, P. adenostyloides, P. auriculata var. matsumurana, were needed to be studied their taxonomic position and distribution in Korea. The somatic chromosome numbers of six taxa, P. adenostyloides, P. auriculata, P. auriculata var. kamtschatica, P. hastata subsp. orientalis, P. firmus, P. pseudotaimingasa were 2n=60 and those of P. firmus and P. pseudotaimingasa were reported first in this study.