• 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.

• Journal of Life Science
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• v.18 no.7
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• pp.1015-1018
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• 2008

To analyze the population genetic structure of the oyster Crassostrea gigas Thunberg, 34 specimens werecollected from Gamak bay in March, 2007. Total genomic DNA was extracted from each sample and PCR was performed to identify haplotypes of oyster by using HCO2918 and LCO1491 primers. Four kinds of haplotypes (CR1, CR2, CR3, and CR4) were identified. Among these group, CR3 showed the highest relative frequency at 73% than any other of haplotypes. On the basis of hierarchical genetic structure, the population of Gamak showed a higher genetic relationship with Namhae, but the genetic distance between southern and western coasts was negative and no statistical significance was found (p>0.05). Consequently, the oyster from Korea coast is determined to be both homogenous and large.

• Animal cells and systems
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• v.16 no.4
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• pp.313-320
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• 2012

Genetic variation was surveyed at four microsatellite loci and 1416 base pairs (bp) of the mitochondrial DNA (mtDNA) cytochrome c oxidase I gene (COI) to clarify the genetic structure of the small yellow croaker, Larimichthys polyactis, in the Yellow and East China Seas, especially regarding four provisional populations, (one Korean and three Chinese populations). Based on microsatellite DNA variations, the estimated expected heterozygosity ($H_E$) in each population ranged from 0.776 to 0.947. The microsatellite pairwise $F_{ST}$ estimates showed no significant genetic differentiation between the populations. MtDNA variations also indicated no genetic structure in L. polyactis, but very high variability. The absence of genetic differentiation among and within populations of L. polyactis may either result from the random migration of the adult or the passive dispersal of the eggs and larvae.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.7
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• pp.915-921
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• 2005

Genetic variation at 25 microsatellite loci, population structure, and genetic bottleneck hypothesis were examined for Ankleshwar poultry population found in Gujrat, India. The estimates of genetic variability such as effective number of alleles and gene diversities revealed substantial genetic variation frequently displayed by microsatellite markers. The average polymorphism across the studied loci and the expected gene diversity in the population were 6.44 and 0.670${\pm}$0.144, respectively. The population was observed to be significantly differentiated into different groups, and showed fairly high level of inbreeding (f = 0.240${\pm}$0.052) and global heterozygote deficit. The bottleneck analysis indicated the absence of genetic bottleneck in the past. The study revealed that the Ankleshwar poultry breed needs appropriate genetic management for its conservation and improvement. The information generated in this study may further be utilized for studying differentiation and relationships among different Indian poultry breeds.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.6
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• pp.1519-1523
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• 2003

Glehnia littoralis Fr. Schmidt (Umbelliferae) is a short-lived herbaceous species that are mostly distributed throughout East Asia. Although G. littoralis has been regarded as ecologically important one, there is no report on population structure in Korea. Starch gel electrophoresis was used to investigate the allozyme variation and genetic structure of Korean populations of this species. A high level of genetic variation was found in G. littoral is populations. Nine enzymes revealed 18 loci, of which 12 were polymorphic (66.7%). Genetic diversity at the species and population levels were 0.159 and 0.129, respectively. The sexual and asexual reproduction, high fecundity, and colonization process are proposed as possible factors contributing to genetic diversity. An indirect estimate of the number of migrants per generation (Nm = 1.45) indicated that gene flow was not extensive among Korean populations of this species. It is suggested that the ability of vegetation and artificial selection may have played roles in shaping the population structure of this species. we recommend that a desirable conservation population should be included at least 30 plants per population and especially those with high variation.

• Korean Journal of Breeding Science
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• v.43 no.1
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• pp.14-22
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• 2011

In this study, 15 simple sequence repeat (SSR) markers were used to analyze the population structure of 55 mungbean accessions (34 from South Asia, 20 from West Asia, 1 sample from East Asia). A total of 56 alleles were detected, with an average of 3.73 per locus. The mean of major allele frequency, expected heterozygosity and polymorphic information content for 15 SSR loci were 0.72, 0.07 and 0.33 respectively. The mean of major allele frequency was 0.79 for South Asia, and 0.74 for West Asia. The mean of genetic diversity and polymorphic information content were almost similar for South Asian and West Asian accessions (genetic diversity 0.35 and polymorphic information content 0.29). Model-based structure analysis revealed the presence of three clusters based on genetic distance. Accessions were clearly assigned to a single cluster in which >70% of their inferred ancestry was derived from one of the model-based populations. 47 accessions (85.56%) showed membership with the clusters and 8 accessions (14.54%) were categorized as admixture. The results could be used to understanding the genetic structure of mungbean cultivars from these regions and to support effective breeding programs to broaden the genetic basis of mungbean varieties.

• Journal of Plant Biotechnology
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• v.50
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• pp.207-214
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• 2023

Lindera obtusiloba (Lauraceae) is a dioecious tree that is widely distributed in the low-altitude montane forests of East Asia, including Korea. Despite its various pharmacological properties and ornamental value, the genetic diversity and population structure of this species in Korea have not been explored. In this study, we selected 6 nuclear and 6 chloroplast microsatellite markers with polymorphism or clean cross-amplification and used these markers to perform genetic diversity and population structure analyses of L. obtusiloba samples collected from 20 geographical regions. Using these 12 markers, we identified a total of 44 alleles, ranging from 1 to 8 per locus, and the average observed and expected heterozygosity values were 0.11 and 0.44, respectively. The average polymorphism information content was 0.39. Genetic relationship and population structure analyses revealed that the natural L. obtusiloba population in Korea is composed of 2 clusters, possibly due to two different plastid genotypes. The same clustering patterns have also been observed in Lindera species in mainland China and Japan.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.443-448
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• 2000

In this paper, multiphase optimization of machine structure is presented. The goal of first step is to obtain (i) light weight, (ii) rigidity statically. In this step, multiple optimization problem with two objective functions is treated using Pareto Genetic Algorithm. Where two objective functions are weight of the structure, and static compliance. The method is applied to a new machine structure design.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.11
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• pp.1631-1635
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• 2007

Japanese Brown cattle, one of the four domestic beef breeds in Japan, are suffering from numerical reduction due to economic pressure from profitable breeds. In this study, all the reproductive cows in the Kouchi sub-breed of the Japanese Brown cattle that were alive in July 2005 were investigated by pedigree analysis to clarify genetic structure and composition of genetic variability. In addition, genetically important individuals for the maintenance of genetic variability of the sub-breed were also identified through the core set method. The number of cows analyzed was 1,349. Their pedigrees were traced back to ancestors born around 1940, and pedigree records of 13,157 animals were used for the analysis. Principal component analysis was performed on the relationship matrix of the cows, and their factor loadings were plotted on a three-dimensional diagram. According to their spatial positions in the diagram, all the cows were subdivided into five genetically distinctive subpopulations of 131 to 437 animals. Genetic diversity of the whole sub-breed, which is estimated to be 0.901, was decomposed into 0.856 and 0.045 of within-subpopulation and between-subpopulation components. Recalculation of genetic diversity after removal of one or several subpopulations from the five subpopulations suggested that three of them were genetically important for the maintenance of genetic variability of the sub-breed. Applying the core set method to all the cows, maximum attainable genetic diversity was estimated to be 0.949, and optimal genetic contributions assigned to each cow supported the previous results indicating relative importance of the three subpopulations as useful genetic materials.

• Journal of Species Research
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• v.1 no.1
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• pp.100-103
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• 2012

Nutria Myocastor coypus is one of a well known invasive riparian mammal found species around world from North America to Eurasia and Africa. In South Korea, feral nutrias inhabit areas from the Nakdonggang and Namgang (River) to their tributaries and Upo Wetland where they have had devastating effects on environment. Nevertheless, there has been little research about nutrias in Korea. This study is to analyze the genetic structure of the nutria population in the Upo Wetland and identify the origin of the source populations. Twenty individuals from the Upo Wetland were genotyped using 25 microsatellite loci. When compared with another introduced population, that of the Blackwater Nation Wildlife Refuge in U.S., the Upo population contains considerable genetic variations. Tests for Hardy-Weinberg equilibrium and Bayesian clustering analysis suggest the Upo population is genetically structured and has at least two source populations. This preliminary study presents the need for further in-depth studies about this species which should combine genetic and ecological studies.