• Korean Journal of Plant Resources
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• v.25 no.3
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• pp.308-316
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• 2012

The purpose of this study was to identify the variant of Platanus occidentalis, whose bark looks white, also can be classified as P. occidentalis and to examine its genetic difference from the general P. occidentalis. For the variant identification of P. occidentalis, SNP and ISSR analysis were used in this study. Thirteen samples of P. occidentalis white variant were collected in Cheongju and 24 samples of normal P. occidentalis obtained in Cheongju, Pyongtaek, Ansan, Suwon, Osan and Jincheon area. ITS 1 and ITS 2 sequences of white variants were identical with those of P. occidentalis. We could not find any sequence difference between normal and white P. occidentalis. So we concluded that the white variant belongs to normal P. occidentalis even their bark is white and peeled easily. By ISSR test, 98 amplicons were acquired using 10 primers. P. occidentalis and white P. occidentalis showed different band patterns from the UBC #834. According to the result of Nei (1979)'s genetic distance analysis, the members of white P. occidentalis were grouped more tightly than the members of normal P. occidentalis. The UPGMA dendrogram shows that the variant and P. occidentalis divided widely into two groups. These results show that the phenotype of P. occidentalis white variant is caused by genetic factors rather than by environmental factors.

• Genomics & Informatics
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• v.8 no.3
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• pp.101-102
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• 2010

During the last decade, large community cohorts have been established by the Korea National Institutes of Health (KNIH), and enormous epidemiological and clinical data have been accumulated. Using these information and samples in the cohorts, KNIH set out to do a large-scale genome-wide association study (GWAS) in 2007, and the Korea Association REsource (KARE) consortium was launched to analyze the data to identify the underlying genetic risk factors of diseases and diverse health indexes, such as blood pressure, obesity, bone density, and blood biochemical traits. The consortium consisted of 6 research divisions, formed by 25 principal investigators in 19 organizations, including 18 universities, 2 institutes, and 1 company. Each division focused on one of the following subjects: the identification of genetic factors, the statistical analysis of gene-gene interactions, the genetic epidemiology of gene-environment interactions, copy number variation, the bioinformatics related to a GWAS, and a GWAS of nutrigenomics. In this special issue, the study results of the KARE consortium are provided as 9 articles. We hope that this special issue might encourage the genomics community to share data and scientists, including clinicians, to analyze the valuable Korean data of KARE.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.5 no.3
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• pp.71-75
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• 2024

In this review, we compared the success rates of DNA amplification and introduced the efficient non-invasive sampling of fecal samples collected from captive and wild Korean long-tailed gorals (Naemorhedus caudatus) by referring to previous non-invasive studies, including three important references (Kim et al., 2008; Kim, 2021; Kim, 2022). A large difference in PCR success rates in the captive and wild populations was observed for mitochondrial (100 and 70.0%), sex-linked (44.4 and 20.8%), and microsatellite markers (73.9 and 34.8%, respectively). Out of the three types of genetic markers, the mitochondrial maker showed the highest success rate, followed by microsatellite and sex-linked markers. In addition, we estimated two factors that affected the PCR success, including the length of the amplified fragments (long, medium, and short) and the type of primer (universal and specific) in fecal samples from a captive population. The length of the PCR fragment was inversely proportional to the PCR success (5.3, 44.4, and 55.6% for long, medium, and short fragments, respectively), and the specific primer set (100%) was more efficient than the universal primer set (60.0%). This review is fundamental but would be greatly helpful for new non-invasive conservation genetic studies, particularly those that use fecal samples from captive and wild populations of rare endangered species. We recommend beginning conservation genetic experiments using mitochondrial markers and then nuclear markers, such as microsatellite and sex-linked markers, to save time, costs, and labor.

• Journal of Life Science
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• v.10 no.1
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• pp.14-19
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• 2000

Variation at 25 allozyme loci in Korean wateralder (Alnus hirsuta Rupr.) from nine distinct populations was measured to estimate the amount and pattern of genetic diversity and population structure. The mean genetic diversity within population was 0.166. Korean alder populations have slightly high levels of genetic diversity compared to those present in associated temperature-zone species and two Canadian alder species. Among population s genetic differentiation accounted for an significant 9% of the total variation. High gene flow(Nm=2.63) was observed. Analysis of fixation indices, calculated for all polymorphic loci in each population, showed a substantial deficiency of heterozygotes relative to Hardy-Weinberg expectations. The mean GST value A. hirsuta in Korea (GST = 0.087) is similar to those of A. rogosa in Canada (GST = 0.052). These low values of GST in two countries. reflecting little spatial genetic differentiation, may indicate extensive gene flow (via pollen and/or seeds) and/or recent colonization. These factors reduce the effect of geographic isolation of breeding and the chance for genetic divergence. A pattern of increasing is observed with increasing rainfall per year. Regression analysis indicates that 54% (F = 4.67) of the variability observed can be explained by this relationship.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.4
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• pp.422-427
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• 1997

Breeding efficiency was investigated to reveal crucial factors for constructing effective breeding system with subdivided populations under equal genetic level. Simulation study of selection experiment was performed for 20 generations with 20 replications each, comparing average breeding values and inbreeding coefficients between the two breeding systems; single population scheme and two population scheme, each of which had the same genetic parameters. Genetic correlations (-0.5 to 0.5) were assumed to be caused only by pleiotropic effect of a gene. Phenotypes of the two traits generated by polygenic effect with additive 36 loci and residuals distributed normally were selected by two traits selection index procedure. Comparing between the single population scheme and the two population scheme, the single population scheme showed higher genetic gain with lower inbreeding coefficient. This result was confirmed particularly for the situation of high selection intensity, high heritability and high degree of unevenness for economic weight. Genetic correlations in the single population scheme were significantly lower than the two population scheme when initial genetic correlation was negative. When terminal crossbreeding for the two population scheme is taken into account, superiority of the two population scheme was suggested. The terminal crossbreeding was effective under the situation of long term selection, existence of moderate inbreeding depression and use of less extreme economic weight.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.2
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• pp.197-202
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• 2020

Objective: The objective of this study was to identify environmental factors strongly associated with and to estimate genetic parameters of reproductive traits in Japanese Black heifers. Methods: Data included reproduction records of Japanese Black heifers born between 2004 and 2014. First service non-return rate (NRR) to 56 days from first to successful insemination (FS), number of services per conception (IN), age at first calving (AFC) and gestation length were analyzed with the use of the general linear model. Genetic parameters were estimated with the use of the univariate animal model of the residual maximum likelihood. Results: Averages of reproductive traits over eleven years were assessed, and the effects of farm, year, month, artificial insemination technician and interaction of farm×year on the traits were determined. Estimated heritability of FS was very low and that of AFC was higher than that of the other traits. A close genetic relation was observed among NRR, IN, and FS; however, their heritabilities were very low. AFC shows favorable genetic correlation with IN and FS. Conclusion: Low heritabilities of most reproductive traits in Japanese Black heifers are strongly influenced by farm management practices, and that large residual variances make genetic evaluation difficult. Among the reproductive traits, AFC is potentially more useful for genetic improvement of heifer reproductive traits because it has high heritability and favorable genetic correlations with IN and FS.

• Journal of Plant Biology
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• v.38 no.4
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• pp.329-336
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• 1995

Raphanus sativus L. var. hortensis f. raphanistroides (wild radish: Brassicaceae), a herbaceous perennial, occurs only on beaches in East Asia. Genetic diversity and population structure of seven Korean populations were investigated using starch gel electrophoresis. Although the Korean populatins are small, isolated with patchy distribution, the population maintain a moderate level of genetic diversity; the mean percentage fo polymorphic loci was 51.4%, mean number of alleles per locus was 1.84, and mean expected heterozygosity was 0.116. A combination of animal-outcrossing breeding system, wide geographical distribution, restricted ecological distribution, and a propensity for high fecundity may in part be explanatory factors contributing the moderate level of genetic diversity within populations. An overall excess of homozygotes relative to Hardy-Weinberg expetations (mean FISa=0.116) indicates that consanguineous mating occur within wild radish populations, leading to a family structure within a circumscribed area. Although population of wild radish experience a limited gene flow, only 5% of the total genetic variation found in Korean wild radish populations examined is due to differences among populations (mean GST=0.052). This value is considerably lower than the mean values of species with similar life history and ecological characteristics. However, significant differences were found in allele frequencies between populations for all polymorphic loci (P<0.01). It is supposed that directional selection toward genetic uniformity (similar gene frequencies) in a relatively homogenous habitat is thought to be operated among Korean wild radish populations.

• Communications for Statistical Applications and Methods
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• v.12 no.3
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• pp.759-771
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• 2005

Twin studies are one of the most widely used methods for quantifying the influence of genetic and environmental factors on some traits such as a life span or a disease. In this paper we propose a genetic mixed linear model for twin survival time data, which allows us to separate the genetic component from the environmental component. Inferences are based upon the hierarchical likelihood (h-likelihood), which provides a statistically efficient and simple unified framework for various random-effect models. We also propose a simple and fast computation method for analyzing a large data set on twin survival study. The new method is illustrated to the survival data in Swedish Twin Registry. A simulation study is carried out to evaluate the performance.

• Environmental Mutagens and Carcinogens
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• v.23 no.1
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• pp.7-10
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• 2003

Hypertension is characterized by multiple genetic and environmental factors. To establish the genetic basis of hypertension in Koreans, we investigated the genetic variations of dopamine D3 receptor (DRD3) gene in the Korean patients with hypertension and normotensive controls. There were no significant differences in the genotype and allele frequencies of Bal I RFLP in the DRD3 gene between two groups, respectively (P > 0.05). Our finding shows lack of association between a genetic marker of DRD3 gene and hypertension, suggesting that the genetic variation of DRD3 gene does not playa major role in the determination of hypertension in Korean population. Further studies in other ethnic groups will be required.

• Journal of Plant Biology
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• v.37 no.3
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• pp.277-284
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• 1994

I investigated levels of genetic diversity, population genetic structure, and gene flow in Hostacapitata, a herbaceous perennial native to South Korea and southwestern Japan. Starch gel electrophoresis was conducted on leaves collected from 310 plants in 19 Korean populations. Twenty-two of 25 putative loci examined were polymorphic in at least one populatin and the mean number of alleles per locus was 1.65. In addition, mean expected heterozygosity within populations (Hep=0.153) was higher than average values for species with similar life history traits. Significant differences in allele frequency were detected between populations at all loci (P<0.01), and slightly over 30% of the genetic variation was found among populatins (GST=0.308). Indirect estimates of the number of migrants per generation (Nm) (0.506, calculated from GST; 0.852, calculated from the mean frequency of ten private alleles) indicate that gene flow is restricted among the isolated Korean populations of H. capitata. Factors contributing to the high levels of genetic differentiation among populations of H. capitata include small and discrete populations, human disturbance, and low frequencies of pollinator foraging behavior.