• Journal of Ecology and Environment
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• v.42 no.3
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• pp.111-119
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• 2018

Background: Juniperus chinensis L. populations are distributed locally on several areas including coastal cliffs which are difficult to access in the central eastern Korea. Wild populations inhabit relatively barren environments such as rocky areas and cliffs, which are very sensitive to even minor environmental disturbances including artificial interventions and natural disturbances, and thus demonstrate great fluctuations in the population size and density. This study aims to analyze the genetic diversity, differentiation, and genetic structure of each population in order to provide useful data required to establish a substantial conservation strategy of J. chinensis. Results: The genetic diversity of J. chinensis at the population level (P = 78.7%, h = 0.282, S.I. = 0.420) was somewhat higher compared with those measured in the same genus, Juniperus. The genetic differentiation degree among nine populations established naturally in central eastern Korea was 11.50% and that among sub-populations within the same area was 5.52%. On the other hand, genetic variation of individuals within the populations was 82.93%. But frequency of the main allele was different among loci. In particular, fixation of allele frequency and occurrence of rare allele in the highly isolated population suggest a likelihood that genetic drift would occur in populations of this plant. As the result of analysis on the genetic structure of nine populations, nearby populations and isolated populations tended to form separate clusters from each other as the hypothetical number of clusters (K) increase. Conclusions: This result implies that if the population size of J. chinensis is reduced due to environmental change and artificial and/or natural disturbances in the future, it could affect negatively on the genetic diversity of the plant species. In order to maintain and conserve genetic diversity of J. chinensis, ecological network, which can help genetic exchange among the local populations, should be prepared, and conservation strategies in situ as well as ex situ are also required with continuous monitoring.

• Animal cells and systems
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• v.8 no.4
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• pp.289-294
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• 2004

Bupleurum latissimum is a narrowly endemic and endangered plant, restricted to only two small populations on steep cliffs of a small island, Ulleung Island, in Korea. The genetic diversity and population differentiation in the two remnant populations of the species were investigated using RAPD (random amplified polymorphic DNA) analysis. The Neis gene diversities were 0.146 in the smaller population of 45 individuals, and 0.151 in the larger population of 61 individuals. The genetic variation was not significantly different between these two populations. Genetic diversity within populations was not low considering the very small size of populations. Analysis of molecular variance (AMOVA) revealed higher variation within populations (65.9%) than genetic differentiation between them (34.1%). B. latissimum revealed higher population differentiation than other outbreeding species. The differentiation of the populations corresponded to low gene flow (Nem = 0.482). The cluster and principal coordination analyses provide strong support for high population differentiation, showing that all individuals of the two populations have built up population-specific clusters. Although gene flow between the two populations of B. latissimum was limited, they have preserved relatively high levels of genetic variation.

• Animal cells and systems
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• v.2 no.2
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• pp.259-267
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• 1998

A deletion of one out of the two copies of 9-bp repeat sequence (CCCCCTCTA), between the cytochrome oxidase II and Iysine tranfer RNA (COII/$tRNA^{Lys}$) genes in human mitochondrial DNA (mtDNA) has been used as a polymorphic anthropological marker for people of east Asian origin, and to lesser extent, Pacific and African populations. We searched for the 9-bp deletion of the intergenic COII/$tRNA^{Lys}$ Lys region in two Korean populations (175 from Seoul and 38 from Cheju) and examine the distibution of this deletion in world populations. The 9-bp deletion was detected directly by electrophoresis of the polymerase chain reaction (PCR)-amplified nucleotide(nt) 8211-8310 mtDNA fragment. The frequencies of the 9-bp deletion were significantly different between the Seoul (16%) and Cheju (8%) populations. Examination of data from the world populations suggests a geographic gradient. The frequency reaches its highest values in some Pacific island populations and decreases along the southeast Asia-Siberia transect. In spite of this geographic gradient, Mongoloid populations including Korean, Chinese, Japanese, and Mongolian populations were relatively homo-geneous with regard to the 9-bp deletion type of the intergenic COII/$tRNA^{Lys}$ region. These results indicate Koreans are genetically related to northeast Asian populations, and have a maternal mongoloid ancestry. Therefore, the 9-bp deletion of the intergenic COII/$tRNA^{Lys}$ region will provide significant information to elucidate the historical patterns of migration of the Mongoloids.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1197-1203
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• 2004

This study deals with the characterization of three populations (two hatchery and one natural) of Indian major carps Catla catla and Labeo rohita from different locations in India. The genetics of Indian major carps has been completely obscure and this is the first report on comparative allozyme variations in natural and hatchery population. The total 10 biochemical genetic markers used to measure interspecific and intraspecific level of diversity. The allele frequency data indicate different level of genetic variability in three populations. The hatchery population exhibited least polymorphism, low level of heterozygosity and genetic diversity.

• Journal of the Korean Society of Tobacco Science
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• v.18 no.1
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• pp.21-29
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• 1996

Tobacco plants resistant (cvs. Xanthi-nc and Samsun-NN) and susceptible (cv. NC 82) to tobacco mosaic virus (TMV) were inoculated with TW to obtain basic information about the characteristics of resistance expression in tobacco plants by examining the viral populations, symptom development and gene expression of pathogenesis-related proteins (PR-proteins) such as PR-1 and $\beta$-1, 3-glucanase in different temperature conditions. TMV populations in resistant plants increased more at 37$^{\circ}C$ than at 27$^{\circ}C$, while the viral populations increased continuously and were not significantly influenced by the temperature conditions in the susceptible tobacco plants. Infection sites of resistant tobacco leaves were remarkably expanded in proportion with increased time at the high temperature.

• Fisheries and Aquatic Sciences
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• v.22 no.6
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• pp.12.1-12.8
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• 2019

Background: Wild fish populations stock is continuously diminishing in the Indo-Ganges river basin, and the population status of most fishes is unidentified. The identification of the population status and the conservation of commercially important and endemic wild fish populations in this region are crucial for the management. The aim of this paper was to identify the population status of Cirrhinus reba, a promising aquaculture but vulnerable species in the Indo-Ganges river basin in Bangladesh. Methods: C. reba samples were collected from four isolated populations of the Brahmaputra (n = 30), the Padma (33), the Karatoya (31), and the Jamuna Rivers (30) in Bangladesh, and the population status was evaluated using morphometric and landmark comparisons. Data were analyzed with the Kruskal-Wallis test, univariate analysis, discriminant function analysis, and the formation of a dendrogram. Results: Three meristic characters (Pectoral fin rays, caudal fin rays, scale in lateral lines), four morphometric characters (head length, pre-orbital length, post-orbital length, maximum body depth), and truss measurement (4-7) were significantly different among the stocks. The step-wise discriminant function analysis retained 15 variables from morphometric and landmark measurements that significantly differentiated the populations based on the constructed DFI and DFII. Discriminate function analysis also showed that 91.2% of the original groups were classified into their correct samples. The cluster analysis of Euclidean distances placed the Jamuna population in one cluster and the Brahmaputra, the Padma, and the Karatoya populations in the second one. Conclusion : Morphological differences among the stock were probably due to different ancestral origin. This is the first report about population status of C. reba in their natural habitat of the Indian subcontinent. Further genetic studies and the evaluation of environmental impact on C. reba populations in Bangladesh are suggested to support our findings.

• The Korean Journal of Malacology
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• v.27 no.4
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• pp.345-351
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• 2011

Comparison of different morphological characteristics of bivalves is very useful for distinguishing species. Therefore, this study used a morphometric approach to document patterns of phenotypic change through the specimens of family Pinnidae inhabiting the bottom sediments at the coasts of An Thoi Archipelago (south-eastern Gulf of Thailand), in that way excluding intraspecific variations among different populations along a wide geographical range. It was revealed that individuals determined as Pinna trigonium separated from specimens of Pinna nigra and Atrina vexillum at high level, but P. nigra and A. vexillum were the single species A. vexillum, as it is assumed now. Also, it was found that both groups of P. trigonium individuals and A. vexillum specimens divided into tree subgroups unified the specimens with the similar morphometric parameters: small, medium and large within the populations, though there were no evident divisions into subgroups in the size distributions of the populations. In addition to the interspecific morphological variations, the species also showed significant intraspecific morphological variations even in the same population. Most probable reason for the appearance of the intraspecific morphological variations and division of all specimens into size-specific subgroups in the population is the fact that the growth of Pinnidae bivalves is not isometric.

• Korean Journal of Plant Taxonomy
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• v.53 no.1
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• pp.9-13
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• 2023

Menyanthes trifoliata L., a heterostyly plant, is an endangered species in Korea. Floral morphology has been published for M. trifoliata, but few works have concentrated on pollen dimorphism differences accompanied by floral dimorphism. Here, we conducted a comparative morphological study of two morphs to investigate a dimorphism system with Korean populations. Pollen morphological characteristics were observed with a light microscope and a scanning electron microscope. For the pin type, pollen size is 36.01 ± 2.01 ㎛, whereas for the thrum type it is 41.28 ± 2.58 ㎛ in terms of the equatorial diameter. The two morphs have a small apocolpium field at 5.62 ± 0.30 for the pin type and 6.24 ± 0.70 for the thrum type. The configuration of the aperture was tricolpate with a striate ridge in the two morphs. However, they have different pollen shapes and sizes, stigma shapes, and apocolpium sizes. M. trifoliata only has different pollen sizes and shapes between European populations and Korean populations. Nevertheless, Korean populations also show pollen dimorphism correlated with their floral dimorphism.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.6
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• pp.776-783
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• 2008

In this study, we investigated the genetic diversity and phylogenetic relationship of six duck populations by employing the genetic polymorphisms of 20 microsatellites. The parameters used in this study included number of alleles, average effective numbers of alleles (E) and average rates of heterozygosity of each population. The results showed that all the microsatellite loci were highly polymorphic except that the locus AJ515896 in Muscovy duck was 0. The average PIC (0.762), average h (0.7843) and average E (5.261) of the six duck populations were all high, indicating that the gene polymorphisms and genetic diversity were high. The test of Hardy-Weinberg equilibrium showed that the six populations in this study were all in Hardy-Weinberg disequilibrium. The F-statistic analysis results showed the range of FST was from 0.0205 (AJ515895) to 0.2558 (AJ515896). The mean FST was 0.0936. Phylogenetic study revealed that Peking duck (Z1 and Z4), Shaoxing duck, Cherry Valley duck and Aobaixing duck were clustered in one group, while the Muscovy duck was clustered in one group alone. The phylogenetic relationships among different populations were in accordance with their breeding history and distribution. Our data suggested that the 20 microsatellite loci were effective markers for analysis of genetic relationships among duck populations.

• Korean Journal Plant Pathology
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• v.13 no.2
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• pp.100-104
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• 1997

Influence of the moisture content in soils was examined on population variations of soil microbes, including Cylindrocarpon destructans causing root rot of ginseng, in vivo and under the field condition. Fungal populations decreased in soils treated with various moisture contents in vivo as days after the treatment in creased, but there was not a significant difference in the population among other treatments except 135% moisture content (flooding) at 15 weeks after the treatment. In flooded soils populations of total fungi and C. destructans were reduced to 1/10 and 1/50 of initial populations, respectively. There was, however, a little difference in the population of total bacteria or Actinomycetes between before and at 15 weeks after flooding. On the other hand, population variations of bacteria and Actinomycetes were much greater than those of fungi at different intervals after the moisture treatment. Variations of microbial populations in flooded soils under the field condition were similar to those in vivo. Especially, populations of Fusarium and pectolytic bacteria in flooded soils were reduced to 1/100 of populations in nonflooded soils at 170 days after treatment.