• Plant Breeding and Biotechnology
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• v.7 no.3
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• pp.272-286
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• 2019

Developing elite hybrid rice varieties is one important objective of rice breeding programs. Several genes related to male sterilities, restores, and pollinators have been identified through map-based gene cloning within natural variations of rice. These identified genes are good targets for introducing genetic traits in molecular breeding. This study was conducted to breed elite hybrid lines with major genes related to hybrid traits and disease/insect resistance in 240 genetic resources and F₁ hybrid combinations of rice. Molecular markers were reset for three major hybrid genes (S5, Rf3, Rf4) and thirteen disease/insect resistant genes (rice bacterial blight resistance genes Xa3, Xa4, xa5, Xa7, xa13, Xa21; blast resistance genes Pita, Pib, Pi5, Pii; brown planthopper resistant genes Bph18(t) and tungro virus resistance gene tsv1). Genotypes were then analyzed using molecular marker-assisted selection (MAS). Biological assay was then performed at the Red River Delta region in Vietnam using eleven F₁ hybrid combinations and two control vatieties. Results showed that nine F₁ hybrid combinations were highly resistant to rice bacterial blight and blast. Finally, eight F₁ hybrid rice varieties with resistance to disease/insect were selected from eleven F₁ hybrid combinations. Their characteristics such as agricultural traits and yields were then investigated. These F₁ hybrid rice varieties developed with major genes related to hybrid traits and disease/insect resistant genes could be useful for hybrid breeding programs to achieve high yield with biotic and abiotic resistance.

• The Korea Journal of Herbology
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• v.28 no.3
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• pp.75-84
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• 2013

Objectives : The origin of Breeae Herba (So-gye) and Cirsii Herba (Dae-gye) is differently prescribed in Korean and Chinese modern pharmacopoeia. Since the similar morphological characteristics and chaotic plant names, moreover, the aerial part of Carduus crispus have been used as the Cirsii Herba. To develop a reliable method for correct identification of these herbal medicines and to evaluate the genetic relationship of these closely related plant species, we analyzed sequences of DNA barcode regions. Methods : Thirty-one samples of 6 medicinal plants (B. segeta, B. setosa, C. japonicum var. maackii, C. setidens, C. chanroenicum, and C. crispus) were collected from different habitate and nucleotide sequences of DNA barcode regions (rDNA-ITS, matK, and rbcL) were analyzed after amplification using appropriate primers reported in previous studies. The nucleotides of species-specific authentic marker and phylogenetic relations were estimated based on the entire sequences of DNA barcodes by the analysis of ClastalW and UPGMA, respectively. Results : In comparative analysis of DNA barcode sequences, we obtained specific nucleotides to discriminate the medicinal plant of Breeae/Cirsii Herba in species level and evaluated the phylogenetic relationship of these species. Futhermore, we identified distinct marker nucleotides enough to authenticate respective species. These sequence differences at corresponding positions were avaliable genetic markers to determine the botanical origins of Breeae Herbal as well as Cirsii Herba. Conclusions : These marker nucleotides would be useful to identify the official herbal medicines by providing of definitive information that can identify each plant species and distinguish from unauthentic adulterants and substitutes.

• Horticultural Science & Technology
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• v.35 no.2
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• pp.232-242
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• 2017

The goal of marker-assisted backcrossing (MAB) is to significantly reduce the number of breeding generations required by using genome-based molecular markers to select for a particular trait; however, MAB systems have only been developed for a few vegetable crops to date. Among the types of molecular markers, SNPs (single-nucleotide polymorphisms) are primarily used in the analysis of genetic diversity due to their abundance throughout most genomes. To develop a MAB system in Chinese cabbage, a high-throughput (HT) marker system was used, based on a previously developed set of 468 SNP probes (BraMAB1, Brassica Marker Assisted Backcrossing SNP 1). We selected a broad-spectrum TuMV (Turnip mosaic virus) resistance (trs) Chinese cabbage line (SB22) as a donor plant, constructing a $BC_1F_1$ population by crossing it with the TuMV-susceptible 12mo-682-1 elite line. Foreground selection was performed using the previously developed trsSCAR marker. Background selection was performed using 119 SNP markers that showed clear polymorphism between donor and recipient plants. The background genome recovery rate (% recurrent parent genome recovery; RPG) was good, with three of 75 $BC_1F_1$ plants showing a high RPG rate of over 80%. The background genotyping result and the phenotypic similarity between the recurrent parent and $BC_1F_1$ showed a correlation. The plant with the highest RPG recovery rate was backcrossed to construct the $BC_2F_1$ population. Foreground selection and background selection were performed using 169 $BC_2F_1$ plants. This study shows that, using MAB, we can recover over 90% of the background genome in only two generations, highlighting the MAB system using HT markers as a highly efficient Brassica rapa backcross breeding system. This is the first report of the application of a SNP marker set to the background selection of Chinese cabbage using HT SNP genotyping technology.

• Horticultural Science & Technology
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• v.34 no.6
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• pp.912-923
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• 2016

Watermelon production is often limited by powdery mildew in areas with a large daily temperature range. Development of resistant watermelon cultivars can protect against powdery mildew; however, little is known about the characteristics of its causal agents. Here, we identified the genus and race of a causal pathogen of powdery mildew in Ansung province of South Korea, and developed molecular markers for the generation of resistant watermelon cultivars. The causal pathogen was determined to be Podosphaera xanthii based on multiple sequence alignments of internal transcribed spacers (ITS) of rDNA. The physiological race was identified as 1W, and the Ansung isolate was named P. xanthii 1W-AN. Following inoculation with the identified P. xanthii 1W-AN, we found inheritance of the resistant gene fitting a single dominant Mendelian model in a segregated population ('SBA' ${\times}$ PI 254744). To develop molecular markers linked to fungus-resistant loci, random amplified polymorphic DNA (RAPD) was accomplished between DNA pooled from eight near-isogenic lines (NILs; $BC_4F_6$), originated from PI 254744 and susceptible 'SBB' watermelon. After sequencing bands from RAPD were identified in all eight NILs and PI254744, 42 sequence-characterized amplifiedregion (SCAR) markers were developed. Overall, 107 $F_2$ plants derived from $BC_4F_6$ NIL-1 ${\times}$ 'SBB' were tested, and one SCAR marker was selected. Sequence comparison between the SCAR marker and the reference watermelon genome identified three Nco I restriction enzyme sites harboring a single nucleotide polymorphism, and codominant cleavage-amplified polymorphic site markers were subsequently developed. A CAPS marker was converted to a high-resolution melt (HRM) marker, which can discriminate C/T SNP (254PMR-HRM3). The 254PMR-HRM3 marker was evaluated in 138 $F_{2:3}$ plants of a segregating population ('SBA' ${\times}$ PI254744) and was presumed to be 4.3 cM from the resistance locus. These results could ensure P. xanthii 1W-AN resistance in watermelon germplasm and aid watermelon cultivar development in marker-assist breeding programs.

• BMB Reports
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• v.49 no.7
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• pp.359-369
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• 2016

DNA methylation is emerging as an attractive marker providing investigative leads to solve crimes in forensic genetics. The identification of body fluids that utilizes tissue-specific DNA methylation can contribute to solving crimes by predicting activity related to the evidence material. The age estimation based on DNA methylation is expected to reduce the number of potential suspects, when the DNA profile from the evidence does not match with any known person, including those stored in the forensic database. Moreover, the variation in DNA implicates environmental exposure, such as cigarette smoking and alcohol consumption, thereby suggesting the possibility to be used as a marker for predicting the lifestyle of potential suspect. In this review, we describe recent advances in our understanding of DNA methylation variations and the utility of DNA methylation as a forensic marker for advanced investigative leads from evidence materials.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.4
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• pp.587-596
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• 2001

In the last decade, rapid developments in molecular biotechnology and of genomic tools have enabled the creation of dense linkage maps across whole genomes of human, plant and animals. Successful development and implementation of interval mapping methodologies have allowed detection of the quantitative trait loci (QTL) responsible for economically important traits in experimental and commercial livestock populations. The candidate gene approach can be used in any general population with the availability of a large resource of candidate genes from the human or rodent genomes using comparative maps, and the validated candidate genes can be directly applied to commercial breeds. For the QTL detected from primary genome scans, two incipient fine mapping approaches are applied by generating new recombinants over several generations or utilizing historical recombinants with identity-by-descent (IBD) and linkage disequilibrium (LD) mapping. The high resolution definition of QTL position from fine mapping will allow the more efficient implementation of breeding programs such as marker-assisted selection (MAS) or marker-assisted introgression (MAI), and will provide a route toward cloning the QTL.

• Journal of Crop Science and Biotechnology
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• v.11 no.4
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• pp.233-236
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• 2008

A positive selectable marker system was adapted for transformation of mature embryo-derived calli of Indica rice (Oryza sativa L.) utilizing the PMI gene encoding for phosphomannose-isomerase that converts mannose-6-phosphate to fructose-6-phosphate. The transformed cells grew on medium supplemented with 3% mannose as carbon source and calli were selected on media containing various concentrations of mannose. Molecular analyses showed that the transformed plants contained the PMI gene. The results indicate that the mannose selection system can be used for Agrobacterium-mediated transformation of mature embryo in rice to substitute the use of conventional selectable markers in genetic transformation.

• Korean Journal of Pharmacognosy
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• v.52 no.2
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• pp.69-76
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• 2021

Cannabis sativa is an important industrial plant utilized to produce fiber, oil, and medicinal ingredients. A chemotype of cannabis is divided into "Drug type" with predominance of tetrahydrocannabinolic acid (THCA) and "Fiber type" with cannabidiolic acid (CBDA). To develop molecular markers for the discrimination of these two types, nucleotide sequences of THCA synthase and CBDA synthase as well as their pseudogenes were retrieved from the recently published cannabis genome in chromosome scale. Gene-specific SNPs were discovered by multiple alignment of these sequences, and 2 dominant marker sets from each gene were designed for selective amplification. Our markers successfully identified "Drug type" and "Fiber type" cannabis plants as well as forensic samples including processed materials. Our molecular markers will provide a fast and efficient system for molecular-based identification of the cannabis plant.

• Parasites, Hosts and Diseases
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• v.37 no.4
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• pp.215-228
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• 1999

To choose one or more appropriate molecular markers or gene regions for resolving a particular systematic question among the organisms at a certain categorical level is still a very difficult process. The primary goal of this review, therefore, is to provide a theoretical information in choosing one or more molecular markers or gene regions by illustrating general properties and phylogenetic utilities of nuclear ribosomal DNA (rDNA) and mitochondrial DNA (mtDNA) that have been most commonly used for phylogenetic researches. The highly conserved molecular markers and/or gene regions are useful for investigating phylogenetic relationships at higher categorical levels (deep branches of evolutionary history). On the other hand, the hypervariable molecular markers and/or gene regions are useful for elucidating phylogenetic relationships at lower categorical levels (recently diverged branches). In summary, different selective forces have led to the evolution of various molecular markers or gene regions with varying degrees of sequence conservation. Thus, appropriate molecular markers or gene regions should be chosen with even greater caution to deduce true phylogenetic relationships over a broad taxonomic spectrum.

• The Korean Journal of Nuclear Medicine
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• v.38 no.2
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• pp.205-208
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• 2004

The two major classes of magnetic resonance (MR) contrast agents are paramagnetic contrast agents, usually based on chelates of gadolinium generating T1 positive signal enhancement, and super-paramagnetic contrast agents that use mono- or polycrystalline iron oxide to generate strong T2 negative contrast in MR images. These paramagnetic or super-paramagnetic complexes are used to develop new contrast agents that can target the specific molecular marker of the cells or tan be activated to report on the physiological status or metabolic activity of biological systems. In molecular imaging science, MR imaging has emerged as a leading technique because it provides high-resolution three-dimension maps of the living subject. The future of molecular MR imaging is promising as advancements in hardware, contrast agents, and image acquisition methods coalesce to bring high resolution in vivo imaging to the biochemical sciences and to patient care.