• Anxiety and mood
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• v.3 no.1
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• pp.3-7
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• 2007

Anxiety disorder is likely caused by an interaction of multiple loci in brain, rather than a single locus. Hyperactive neurotransmitter circuits between the cortex, thalamus, amygdala, and hypothalamus are responsible for production of anxiety symptoms. Familial studies performed on anxiety disorder suggested that anxiety disorder should be caused by genetic etiology. Numerous linkage and association studies showed different genetic loci of anxiety disorder. Candidate genes have been focused on important neurotransmitters, neuropeptide, or genes affecting neuronal growth, development, protection or apoptosis. Anxiety disorder has various symptoms and comorbid diseases in family or proband. Therefore, further studies focused on symptomatic dimension of anxiety disorder or responses to drugs are required.

• Korean Journal of Biological Psychiatry
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• v.5 no.1
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• pp.17-33
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• 1998

Advances in molecular biology contribute to the understanding genetic mechanism of psychiatric disorders. They have renewed hope for the discovery of disease relevant gene. However, the results somewhat confused. And we will wait for a long time for the application of gene therapy in schizophreniar. Fortunately we could classified the schizophrenia with genotypes of dopamine and serotonin receptors. It is expected that this genetic classification could provide key strategy for the therapeutic application in biological treatment for schizophrenia. The purpose of this article is to call attention of the institute participants to linkage, association, mRNA expression, genotypic classification and to the need for more systemic research. The author summarized the modified methods which were done in his laboratory in appendix.

• Animal cells and systems
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• v.8 no.1
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• pp.41-47
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• 2004

The kallikrein-kinin system affects regulation of blood pressure, and genes encoding for the components of this system have been considered as good candidates for hypertension. To evaluate the relationship between genetic polymorphisms of candidate genes involved in this system and hypertension, we performed case-control studies using genetic markers in Korean normotensives and hypertensives, respectively. By association study, there was a marginal association with hypertension in AA genotype distribution of A1789G polymorphism in the hKLK1 gene (P=0.0754). Thus, this genetic polymorphism may weakly contribute to the susceptibility to hypertension in Koreans. We also observed that significant linkage disequilibrium exists among three polymorphic sites in the hKLK1 gene studied, suggesting that the three genetic polymorph isms can be useful as genetic markers in clinical association studies. Further studies using larger sample sizes and more genetic markers will be needed to clarify genetic influence of kallikrein-kinin system for hypertension.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.5
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• pp.423-428
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• 2004

Soybean seeds contain high amounts of isoflavones that display biological effects and isoflavone content of soybean seed can vary by year, environment, and genotype. Objective of this study was to identify quantitative trait loci that underlie isoflavone content in soybean seeds. The study involved 85 $F_2$ populations derived from Korean soybean cultivar 'Kwangkyo' and wild type soybean 'IT182305' for QTL analysis associated with isoflavone content. Isoflavone content of seeds was determined by HPLC. The genetic map of 33 linkage groups with 207 markers was constructed. The linkage map spanned 2,607.5 cM across all 33 linkage groups. The average linkage distance between pair of markers among all linkage groups was 12.6 cM in Kosambi map units. Isoflavone content in $F_2$ generations varied in a fashion that suggested a continuous, polygenic inheritance. Eleven markers (4 RAPD, 3 SSR, 4 AFLP) were significantly associated with isoflavone content. Only two markers, Satt419 and CTCGAG3 had F-tests that were significant at P<0.01 in $F_2$ generation for isoflavone content. Interval mapping using the $F_2$ data revealed only two putative QTLs for isoflavone content. The peak QTL region on linkage group 3, which was near OPAG03c, explained $14\%$ variation for isoflavone content. The peak QTL region on linkage group 5, which was located near OPN14 accounted for $35.3\%$ variation for isoflavone content. Using both Map-Maker-QTL $(LOD{\geq}2.0)$ and single-factor analysis $(P{\leq}0.05)$, one marker, CTCGAG3 in linkage group 3 was associated with QTLs for isoflavone content. This information would then be used in identification of QTLs for isoflavone content with precision

• Molecules and Cells
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• v.24 no.1
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• pp.60-68
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• 2007

Microsatellites, also called simple sequence repeats (SSR), are very useful molecular genetic markers commonly used in crop breeding, species identification and linkage analysis. In the present study, we constructed a microsatellite-enriched genomic library of Panax ginseng, and identified 251 novel microsatellite sequences. Tri-nt repeat units were the most abundant (46.6%), followed by di-nt repeats (35.5%). The $(AG)_n$ motif was most common (23.1%), followed by the $(AAC)_n$ motif (22.3%). From the genotyping of 94 microsatellites using marker-specific primer sets, we identified 11 intraspecific polymorphic markers as well as 14 possible interspecific polymorphic markers differing between P. ginseng and P. quinquefolius. The exact allele structures of the polymorphic markers were determined and the alleles were named. This study represents the first report of the bulk isolation of microsatellites by screening a microsatellite-enriched genomic library in P. ginseng. The microsatellite markers could be useful for linkage analysis, genetic breeding and authentication of Panax species.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.166-170
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• 1999

The identification of quantitative trait loci (QTL) has the potential to enhance the efficiency of im- proving food processing traits of soybean. In this study, 92 restriction fragment length polymorphism (RFLP) loci and two morphological markers (W$_1$ and T) were used to identify QTL associated with food processing traits of soybean for sprout in 83 F$_2$-derived lines from a cross of ＇Pureun＇ x ＇Jinpum 2＇. The genetic map consisted of 76 loci which covered about 760 cM and converged into 20 linkage groups. Eighteen markers remained unlinked. Phenotypic data were collected for hypocotyl length, abnormal seedling rate, and sprout yield seven days after seed germination at 2$0^{\circ}C$. Based on the single-factor analysis of variance, eight independent markers were associated with hypocotyl length. Four of seven markers associated with abnormal seedling rate were identified as independent. Seven loci were associated with sprout yield. For three different traits, much of genetic variation was explained by the identified QTL in this population. Several RFLP markers in linkage group (LG) Bl were detected as being associated with three traits, providing a genetic explanation for the biological correlation of sprout yield with hypocotyl length (r=OA07＊＊＊) and with abnormal seedling rate (r=-406＊＊＊).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.4
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• pp.227-231
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• 2000

Small seed size is one of the major traits of soybean cultivars for sprouts with regard to high sprout yield. This study was conducted to identify quantitative trait loci (QTL) for seed size and weight in a set of F 6 seeds of 89 lines derived from a cross between 'Pureunkong', a soybean cultivar developed for sprouts and 'Jinpumkong 2', a soybean cultivar with no beany taste in seed due to the lack of lipoxygenases. The genetic map of 25 linkage groups with a total of 98 markers including RFLP, RAPD, SSR and classical markers was constructed from this F/sbu 5/-derived population and was used for QTL analysis. 'Pureunkong' was significantly smaller (P＜0.01) than 'Jinpumkong 2' in seed size and seed weight. Genetic variation was detected and transgressive segregation was common in the population for these traits. Seven DNA markers including opT14-1600 in LG A2, opF02-400 in LG B2, Satt100, opC09-700, opG04-730 and opQll-650 in LG C2, and opY07-1100 ＆ 1000 in LG(unknown) were significantly associated and accounted for 4.7 to 10.9% and 5.1 to 10.1 % of the phenotypic variation in seed size and seed weight, respectively. 'Pureunkong' alleles increased seed size and seed weight at the all four significant marker loci on the LG C2. These marker loci in LG C2 were closely linked and were presumed to be a single QTL. Overall, at least three independent QTLs from 3 linkage groups (A2, B2, and C2) were putatively involved in the control of seed size and seed weight.

• Journal of Preventive Medicine and Public Health
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• v.37 no.4
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• pp.366-372
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• 2004

Objectives : This study was conducted to propose a new transmission/disequilibrium test(TDT) to test the linkage between genetic markers and disease-susceptibility genes based on haplotypes. Simulation studies were performed to compare the proposed method with that of Zhao et al. in terms of type I error probability and powers. Methods : We estimated the haplotype frequencies using the expectation-maximization(EM) algorithm with parents genotypes taken from a trio dataset, and then constructed a two-way contingency table containing estimated frequencies to all possible pairs of parents haplotypes. We proposed a score test based on differences between column marginals and their corresponding row marginals. The test also involved a covariance structure of marginal differences and their variances. In simulation, we considered a coalescent model with three genetic markers of biallele to investigate the performance of the proposed test under six different configurations. Results : The haplotype-based TDT statistics, our test and Zhao et al.'s test satisfied a type I error probability, but the TDT test based on single locus showed a conservative trend. As expected, the tests based on haplotypes also had better powers than those based on single locus. Our test and that of Zhao et al. were comparable in powers. Conclusion : We proposed a TDT statistic based on haplotypes and showed through simulations that our test was more powerful than the single locus-based test. We will extend our method to multiplex data with affected and/or unaffected sibling(s) or simplex data having only one parent s genotype.

• Genomics & Informatics
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• v.3 no.4
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• pp.149-153
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• 2005

Asthma is an inflammatory airways disease characterized by bronchial hyperresponsiveness and airways obstruction, which results from a complex interaction of genetic and environmental factors. Interleukin (IL)-13 and IL-4 are important in IgE synthesis and allergic inflammation, therefore genes encoding IL-13 and IL-4 are candidates for predisposition to asthma. In the present study, we screened single-nucleotide polymorphisms (SNPs) in IL-13 and IL-4 and examined whether they are risk factors for asthma. We resequenced all exons and the promoter region in 12 asthma patients and 12 normal controls, and identified 18 SNPs including 2 novel SNPs. The linkage disequilibrium(LD) pattern was evaluated with 16 common SNPs, and haplotypes were also estimated within the block. Although IL-13 and IL-4 are localized within 27 kb on chromosome 5q31 and share many biological profiles, this region was partitioned into 2 blocks. One SNP and three SNPs were determined as haplotype-taggingSNPs (htSNPs) within IL-13 and IL-4 haplotype-block, respectively. No significant associations were observed between any of the SNPs or haplotypes and development of asthma in small number of Korean subjects. However, the genetic variants of IL-13 and IL-4 would provide valuable strategies for the genotyping studies in large population.

• Journal of Animal Science and Technology
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• v.57 no.12
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• pp.47.1-47.10
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• 2015

Background: Knowledge of linkage disequilibrium (LD) levels among different populations can be used to detect genetic diversity and to investigate the historical changes in population sizes. Availability of large numbers of SNP through new sequencing technologies has provided opportunities for extensive researches in quantifying LD patterns in cattle breeds. The aim of this study was to compare the extent of linkage disequilibrium among Iranian cattle breeds using high density SNP genotyping data. Results: A total of 70 samples, representing seven Iranian indigenous cattle breeds, were genotyped for 777962 SNPs. The average values of LD based on the $r^2$ criterion were computed by grouping all syntenic SNP pairwises for intermarker distances from 0 Kb up to 1 Mb using three distance sets. Average $r^2$ above 0.3 was observed at distances less than 30 Kb for Sistani and Kermani, 20 Kb for Najdi, Taleshi, Kurdi and Sarabi, and 10 Kb for Mazandarani. The LD levels were considerably different among the Iranian cattle breeds and the difference in LD extent was more detectable between the studied breeds at longer distances. Lower level of LD was observed for Mazandarani breed as compared to other breeds indicating larger ancestral population size in this breed. Kermani breed continued to have more slowly LD decay than all of the other breeds after 3 Kb distances. More slowly LD decay was observed in Kurdi and Sarabi breeds at larger distances (>100 Kb) showing that population decline has been more intense in more recent generations for these populations. Conclusions: A wide genetic diversity and different historical background were well reflected in the LD levels among Iranian cattle breeds. More LD fluctuation was observed in the shorter distances (less than 10 Kb) in different cattle populations. Despite of the sample size effects, High LD levels found in this study were in accordance with the presence of inbreeding and population decline in Iranian cattle breeds.