• Genomics & Informatics
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• v.12 no.3
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• pp.87-97
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• 2014

Although the number of protein-coding genes is not highly variable between plant taxa, the DNA content in their genomes is highly variable, by as much as 2,056-fold from a 1C amount of 0.0648 pg to 132.5 pg. The mean 1C-value in plants is 2.4 pg, and genome size expansion/contraction is lineage-specific in plant taxonomy. Transposable element fractions in plant genomes are also variable, as low as ~3% in small genomes and as high as ~85% in large genomes, indicating that genome size is a linear function of transposable element content. Of the 2 classes of transposable elements, the dynamics of class 1 long terminal repeat (LTR) retrotransposons is a major contributor to the 1C value differences among plants. The activity of LTR retrotransposons is under the control of epigenetic suppressing mechanisms. Also, genome-purging mechanisms have been adopted to counter-balance the genome size amplification. With a wealth of information on whole-genome sequences in plant genomes, it was revealed that several genome-purging mechanisms have been employed, depending on plant taxa. Two genera, Lilium and Fritillaria, are known to have large genomes in angiosperms. There were twice times of concerted genome size evolutions in the family Liliaceae during the divergence of the current genera in Liliaceae. In addition to the LTR retrotransposons, non-LTR retrotransposons and satellite DNAs contributed to the huge genomes in the two genera by possible failure of genome counter-balancing mechanisms.

• Plant Biotechnology Reports
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• v.5 no.4
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• pp.317-322
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• 2011

We determined the nuclear DNA content (genome size) of over 35 accessions each of bamboo and rattan species from Southeast Asia. The 2C DNA per nucleus was quantified by flow cytometry. The fluorescence of nuclei isolated from the leaves and stained with propidium iodide was measured. The genome size of the bamboo species examined was between 2.5 and 5.9 pg DNA per 2C nucleus. The genome size of the rattan species examined ranged from 1.8 to 10.5 pg DNA per 2C nucleus. This information will be useful for scientists working in diverse areas of plant biology such as biotechnology, biodiversity, genome analysis, plant breeding, physiology and molecular biology. Such data may be utilized to attempt to correlate the genome size with the ploidy status of bamboo species in cases where ploidy status has been reported.

• Korean Journal of Plant Taxonomy
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• v.49 no.4
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• pp.334-344
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• 2019

The genome size is defined as the amount of DNA in an unreplicated gametic chromosome complement and is expressed as the 1C value. It is a fundamental parameter of organisms that is useful for studies of the genome, as well as biodiversity and conservation. The genome sizes of Korean plants, including Carex (Cyperaceae), have been poorly reported. In this study, we report the genome sizes of 43 species and infraspecific taxa of Korean Carex using flow cytometry, and these results represent about 24.4% of the Carex species and infraspecific taxa distributed on the Korean peninsula. The Plant DNA C-Value Database (release 7.1) updated with and now including our data (a total of 372 Carex accessions) shows that the average genome size of members of the Carex species is 0.47 pg (1C), and the largest genome (C. cuspidate Bertol.; 1C = 1.64 pg) is 8.2 times larger than the smallest (C. brownii Tuck., C. kobomugi Ohwi, C. nubigena D. Don ex Tilloch & Taylor, and C. paxii Kuk.; 1C = 0.20 pg). The large genomes are frequently found in the subgen. Carex, especially in sect. Aulocystis, sect. Digitatae, sect. Glaucae, sect. Paniceae, and sect. Siderostictae. Our data updates the current understanding of genome sizes in Carex. This will serve as the basis for understanding the phylogeny and evolution of Carex and will be especially useful for future genome studies.

• Korean Journal of Plant Taxonomy
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• v.47 no.2
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• pp.161-169
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• 2017

The genome size is one of the basic characters of an organism, and it is widely applied in various fields of biology, such as systematics, breeding biology, population biology, and evolutionary biology. This factor was recently highlighted in genome studies because choosing a representative of a plant group having the smallest genome size is important for the efficiency of a genome project. For the estimation of the genome size, flow cytometry has recently been highlighted because it is a convenient, fast, and reliable method. In this study, we report the genome sizes of 15 taxa of Lamiaceae from nine genera distributed in Korea using flow cytometry. Data pertaining to the genome size for all of our species have not been reported thus far, and the data from Agastache, Clinopodium, Elsholtzia, and Isodon are the first reported for each genus. The genome sizes of 15 genera and 39 species were reported to the Plant DNA C-values Database (http://data.kew.org/cvalues/). Scutellaria indica L. has a genome size of 0.37 pg (1C). This is the fourth smallest value among the 98 Lamiaceae taxa in the Angiosperm DNA C-value Database, indicating that this taxon can be used as a reference species in the genome studies in Lamiaceae as a native Korean species. The largest genome size observed in this study is in Phlomis umbrosa Turcz. (1C=2.60 pg), representing the possible polyploidy origin of this species in the family.

• ALGAE
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• v.31 no.4
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• pp.373-378
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• 2016

Cochlodinium polykrikoides is a red-tide forming dinoflagellate that causes significant worldwide impacts on aquaculture industries and the marine ecosystem. There have been extensive studies on managing and preventing C. polykrikoides blooms, but it has been difficult to identify an effective method to control the bloom development. There is also limited genome information on the molecular mechanisms involved in its various ecophysiology and metabolism processes. Thus, comprehensive genome information is required to better understand harmful algal blooms caused by C. polykrikoides. We estimated the C. polykrikoides genome size using flow cytometry, with detection of the fluorescence of DNA stained with propidium iodide (PI). The nuclear genome size of C. polykrikoides was 100.97 Gb, as calculated by comparing its mean fluorescence intensity (MFI) to the MFI of Mus musculus, which is 2.8 Gb. The exceptionally large genome size of C. polykrikoides might indicate its complex physiological and metabolic characteristics. Our optimized protocol for estimating the nuclear genome size of a dinoflagellate using flow cytometry with PI can be applied in studies of other marine organisms.

• Journal of Microbiology
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• v.44 no.5
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• pp.530-536
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• 2006

Bacteriophage P4, a satellite phage of coliphage P2, is a very useful experimental tool for the study of viral capsid assembly and cos-cleavage. For an in vitro cos-cleavage reaction study of the P2-P4 system, new shortened and selectable markers containing P4 derivative plasm ids were designed as a substrate molecules. They were constructed by swapping the non-essential segment of P4 DNA for either the kanamycin resistance (kmr) gene or the ampicillin resistance (apr) gene. The size of the genomes of the resulting markers were 82% (P4 ash8 delRI:: kmr) and 79% (P4 ash8 delRI:: apr) of the wild type P4 genome. To determine the lower limit of genome size that could be packaged into the small P4-size bead, these shortened P4 plasmids were converted to phage particles with infection of the helper phage P2. The conversion of plasmid P4 derivatives to bacteriophage particles was verified by the heat stability test and the burst size determination experiment. CsCl buoyant equilibrium density gradient experiments confirmed not only the genome size of the viable phage form of shortened P4 derivatives, but also their packaging into the small P4-size head. P4 ash8 delRI:: apr turned out to be the smallest P4 genome that can be packaged into P4-sized head.

• Journal of Preventive Medicine and Public Health
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• v.40 no.2
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• pp.95-101
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• 2007

Focusing on complex diseases of public health significance, strategic issues regarding the on-going Korean Genome Cohort were reviewed: target size and diseases, measurements, study design issues, and follow-up strategy of the cohort. Considering the epidemiologic characteristics of Korean population as well as strengths and drawbacks of current research environment, we tried to tailor the experience of other existing cohorts into proposals for this Korean study. Currently 100,000 individuals have been participating the new Genome Cohort in Korea. Target size of de novo collection is recommended to be set as between 300,000 to 500,000. This target size would allow acceptable power to detect genetic and environmental factors of moderate effect size and possible interactions between them. Family units and/or special subgroups are recommended to parallel main body of adult individuals to increase the overall efficiency of the study. Given that response rate to the conventional re-contact method may not be satisfactory, successful follow-up is the main key to the achievement of the Korean Genome Cohort. Access to the central database such as National Health Insurance data can provide enormous potential for near-complete case detection. Efforts to build consensus amongst scientists from broad fields and stakeholders are crucial to unleash the centralized database as well as to refine the commitment of this national project.

• BMB Reports
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• v.39 no.4
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• pp.418-425
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• 2006

A human bacterial artificial chromosome (BAC) library was constructed with high molecular weight DNA extracted from the blood of a male Korean. This Korean BAC library contains 100,224 clones of insert size ranging from 70 to 150 kb, with an average size of 86 kb, corresponding to a 2.9-fold redundancy of the genome. The average insert size was determined from 288 randomly selected BAC clones that were well distributed among all the chromosomes. We developed a pooling system and three-step PCR screen for the Korean BAC library to isolate desired BAC clones, and we confirmed its utility using primer pairs designed for one of the clones. The Korean BAC library and screening pools will allow PCR-based screening of the Korean genome for any gene of interest. We also determined the allele types of HLA-DRA and HLA-DRB3 of clone KB55453, located in the HLA class II region on chromosome 6p21.3. The HLA-DRA and DRB3 genes in this clone were identified as the DRA*010202 and DRB3*01010201 types, respectively. The haplotype found in this library will provide useful information in future human disease studies.

• Genomics & Informatics
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• v.14 no.3
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• pp.90-95
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• 2016

Nuclear mitochondrial DNA segment (Numt) insertion describes a well-known phenomenon of mitochondrial DNA transfer into a eukaryotic nuclear genome. However, it has not been well understood, especially in plants. Numt insertion patterns vary from species to species in different kingdoms. In this study, the patterns were surveyed in nine plant species, and we found some tip-offs. First, when the mitochondrial genome size is relatively large, the portion of the longer Numt is also larger than the short one. Second, the whole genome duplication event increases the ratio of the shorter Numt portion in the size distribution. Third, Numt insertions are enriched in exon regions. This analysis may be helpful for understanding plant evolution.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.24-24
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• 2019

Iris L. is a perennial genus comprising approximately 300 species worldwide, with the greatest number of endemic species occurring in Asia. Iris is one of the largest genera in the family Iridaceae and includes ca. 15 species native to Korea. Although chromosome number change, karyotype restructuring, and genome size variation play an important role in plant genome diversification, understanding the karyotype variation in Korean Iris species has been hampered by the wide range of base chromosome number (x = 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22) reported to date. This study documents the chromosome numbers, karyotype structure and genome size variation in Iris ruthenica K. Gawl., an endangered species in Korea obtained using classic Feulgen staining and flow cytometry. The chromosome number of all investigated plants from the nine populations was 2n = 42. All individuals studied possessed metacentric and submetacentric chromosomes. The genome size of the I. ruthenica in eight wild populations ranged from 2.39 pg/1C to 2.45 pg/1C ($2.42{\pm}0.02pg/1C$: $mean{\pm}SD$). This study provides the first report of genome size variation in Iris ruthenica in Korea. This study lays foundation for cytogenetic further analyses employing by fluorescence in situ hybridization (FISH) to better understand the chromosomal evolution in this species and in the whole genus.