• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.127-145
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• 2011

Various environmental ecosystems are valuable sources for microbial ecology studies, and their analyses using recently developed molecular ecological approaches have drawn significant attention within the scientific community. Changes in the microbial community structures due to various anthropogenic activities can be evaluated by various culture-independent methods e.g. ARISA, DGGE, SSCP, T-RFLP, clone library, pyrosequencing, etc. Direct amplification of total community DNA and amplification of most conserved region (16S rRNA) are common initial steps, followed by either fingerprinting or sequencing analysis. Fingerprinting methods are relatively quicker than sequencing analysis in evaluating the changes in the microbial community. Being an efficient, sensitive and time- and cost effective method, T-RFLP is regularly used by many researchers to access the microbial diversity. Among various fingerprinting methods T-RFLP became an important tool in studying the microbial community structure because of its sensitivity and reproducibility. In this present review, we will discuss the important developments in T-RFLP methodology to distinguish the total microbial diversity and community composition in the various ecosystems.

• Journal of Plant Biology
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• v.37 no.2
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• pp.141-149
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• 1994

Levels of genetic diversity, population genetic structure, and gene flow in Hosta yingeri, a herbaceous perennial endemic to Taehuksan, Sohuksan, and Hong Islands, were investigated. Starch gel electrophoresis was conducted on leaves for 101 plants collected from three populations. Although the distribution of thespecies is restricted in the islands, it maintains high levels of genetic variatin; 64% of polymorphic loci in at least one population (Ps), the mean number of alleles per locus (Ap) of 1.92, and the mean effective number of alleles per locus (Aep) of 1.52. Overall, mean genetic diversity (Hep=0.250) was substantially higher than mean estimate for species with very similarlife history traits (0.102). Large populaton size, the persistence of multiple generations within populations, high fecundity, predominantly outcrossing breeding system, large size of pollinator visitation areas may be explanatory factors contributing the higher level of genetic diversity maintained within populations. Analysis of fixation indices showed an overall slight excess of heterozygotes (mean FIS=-0.066) relative to Hardy-Weinberg expectations, which may in part be due to the near self-incompatible breeding system in the species. Significant differences in allele frequencies among populaitns were found for 14 out of 16 polymorphic loci (P<0.05). Slightly more than 80% of the total variation in the species was common to all populations (GST=0.198). As expected, indirect estimate of the number of migrants per generation (Nm=0.45, calculated from mean GST) and nine private alleles found in the three populations indicate that gene movement among three isolated island populations was low.

• 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.

• Parasites, Hosts and Diseases
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• v.55 no.5
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• pp.465-472
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• 2017

Recent trends of malaria in Thailand illustrate an increasing proportion of Plasmodium vivax, indicating the importance of P. vivax as a major causative agent of malaria. P. vivax malaria is usually considered a benign disease so the knowledge of this parasite has been limited, especially the genetic diversity and genetic structure of isolates from different endemic areas. The aim of this study was to examine the population genetics and structure of P. vivax isolates from 4 provinces with different malaria endemic settings in Thailand using 6 microsatellite markers. Total 234 blood samples from P. vivax mono-infected patients were collected. Strong genetic diversity was observed across all study sites; the expected heterozygosity values ranged from 0.5871 to 0.9033. Genetic variability in this study divided P. vivax population into 3 clusters; first was P. vivax isolates from Mae Hong Son and Kanchanaburi Provinces located on the western part of Thailand; second, Yala isolates from the south; and third, Chanthaburi isolates from the east. P. vivax isolates from patients having parasite clearance time (PCT) longer than 24 hr after the first dose of chloroquine treatment had higher diversity when compared with those having PCT within 24 hr. This study revealed a clear evidence of different population structure of P. vivax from different malaria endemic areas of Thailand. The findings provide beneficial information to malaria control programme as it is a useful tool to track the source of infections and current malaria control efforts.

• Animal Systematics, Evolution and Diversity
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• v.27 no.2
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• pp.151-158
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• 2011

Fish community structure in the Pyeongchanggang River was investigated from April to November 2009. About 900 individuals representing 24 species from eight families at six sites in the Pyeongchanggang River were collected. It was similar to the 2001's survey and it was less than 2006's survey. The Korean endemic species, Zacco koreanus was the most abundant, whereas subdominant species were native species, such as Pungtungia herzi, Zacco platypus, Rhynchocypris kumgangensis and Rhynchocypris oxycephalus. Three endangered species were collected at the sampling area, Acheilognathus signifier (relative abundance [RA] 0.9%), Pseudopungtungia tenuicorpa (RA 1.4%), and Cottus koreanus (RA 3.6%). One natural monument species, Hemibarbus mylodon, was included. According to the analysis of ecological indicator characteristics, the relative proportion of tolerant species was 6.3% (57 individuals), whereas the proportion of sensitive species was 65.9% (593 individuals). Species evenness, richness and diversity indices decreased gradually through the month from April to November during the study. Community indices in Pyeongchanggang River showed a high evenness index (J'>0.6), a low level of species richness (R<3.5) and a medium level of diversity (1.5

• 한국해양학회지
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• v.14 no.1
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• pp.32-38
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• 1979

The original concept and theory of Shannon's function H=-$\Sigma$(i-1,n)Pi, log$\_$2/Pi and its applicable domains in ecology are discussed. The confusions exist in use and interpretation of this function are due to: 1. Mixing the idea of proper ecological diversity with that of Shannon's information theory. 2. Confusion of physical or thermodynamical systems with ecological systems. 3. Confusion of the system from which one had calculated function H with the system of which function H is interpreted. It's proposed to use function H for the comparison of community's structure and so, for the distinction of community's evolution (succession) steps.

• Journal of Animal Science and Technology
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• v.65 no.5
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• pp.912-921
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• 2023

Genetic diversity analysis is crucial for maintaining and managing genetic resources. Several studies have examined the genetic diversity of Korean domestic chicken (KDC) populations using microsatellite markers, but it is difficult to capture the characteristics of the whole genome in this manner. Hence, this study analyzed the genetic diversity of several KDC populations using high-density single nucleotide polymorphism (SNP) genotype data. We examined 935 birds from 21 KDC populations, including indigenous and adapted Korean native chicken (KNC), Hyunin and Jeju KDC, and Hanhyup commercial KDC populations. A total of 212,420 SNPs of 21 KDC populations were used for calculating genetic distances and fixation index, and for ADMIXTURE analysis. As a result of the analysis, the indigenous KNC groups were genetically closer and more fixed than the other groups. Furthermore, Hyunin and Jeju KDC were similar to the indigenous KNC. In comparison, adapted KNC and Hanhyup KDC populations derived from the same original species were genetically close to each other, but had different genetic structures from the others. In conclusion, this study suggests that continuous evaluation and management are required to prevent a loss of genetic diversity in each group. Basic genetic information is provided that can be used to improve breeds quickly by utilizing the various characteristics of native chickens.

• The Plant Pathology Journal
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• v.29 no.4
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• pp.435-439
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• 2013

Rice blast fungus, Magnaporthe oryzae, inflicts serious damage to global rice production. Due to high variability of this fungal pathogen, resistance of newly-released rice cultivars is easily broken down. To understand the population structure of M. oryzae, we analyzed the genetic diversity of the Korean population using multilocus microsatellite typing. Eleven microsatellite markers were applied to the population of 190 rice isolates which had been collected in Korea for two decades since the 1980's. Average values of gene diversity and allele frequency were 0.412 and 6.5, respectively. Comparative analysis of the digitized allele information revealed that the Korean population exhibited a similar level of allele diversity to the integrated diversity of the world populations, suggesting a particularly high diversity of the Korean population. Therefore, these microsatellite markers and the comprehensive collection of field isolates will be useful genetic resources to identify the genetic diversity of M. oryzae population.

• Korean Journal of Environment and Ecology
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• v.25 no.4
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• pp.540-561
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• 2011

We carried out a study for ecological management and ideal vegetation structure selection on the shrine forest of 'Miwhang-sa' considering the species diversity and the vegetation structure analysis associated with global warming. We carried out the analyses of phytosociological vegetation structure, correlation between vegetation units and environmental variables, life form, species diversity, and species evenness. This study identified the vegetation units as 3 communities. The identified vegetation units are as follows: Quercus acuta community(DQ), Quercus serrata-Quercus variabilis community(QQ) and Celtis sinensis community(CS). According to the basis on the environmental variables; Ca, Mg and P, Celtis sinensis community and other communities were classified. Quecus serrata-Quercus variabilis comm. and Quercus acuta comm. were classified, according to the basis on the environmental variables; organic matter(OM), Ni and Zn. Sasa borealis as life form R1-2, dominated the herb layer and will dominate the herb and shrub layers. Species simplification is formed on herb layer and will be formed on shrub layer. The species diversity of Quercus serrata-Quercus variabilis community is higher than the one of Quercus acuta community, and the species diversity of shrine forest around Miwhang-sa was higher than the shrine forest around Nameun-sa where evergreen broad-leaved forests dominate. It is essential that the long-term vegetation management considering the vegetation units by phytosociological analysis, the species simplification problem of low layers by S. borealis and the species diversity and evenness in the shrine forest, Miwhang-sa.

• Weed & Turfgrass Science
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• v.2 no.3
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• pp.230-235
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• 2013

Amaranths (Amaranthus sp.), an endemic American crop, are now grown widely across the world. This study used 14 simple sequence repeat (SSR) markers to analyze the genetic diversity of 74 amaranth accessions from the United States, with eight accessions from Australia as controls. One hundred twenty-two alleles, averaging eight alleles per locus, were observed. The average major allele frequency, expected heterozygosity, and polymorphism information content (PIC) were 0.44, 0.69, and 0.65, respectively. The structure analysis based on genetic distance classified 77 accessions (94%) into three clusters, while five accessions (6%) were admixtures. Among the three clusters, Cluster 3 had the highest allele number and PIC values, while Cluster 2 had the lowest. The lowest FST was between Clusters 1 and 3, indicating that these two clusters have higher gene flow between them compared to the others. This finding was reasonable because Cluster 2 included most of the Australian accessions. These results indicated satisfactory genetic diversity among U.S. amaranths. These findings can be used to design effective breeding programs involving different plant characteristics.