• Title/Summary/Keyword: Geographic variation

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Analysis of 3 Dimension Topography by Real-Time Kinematic GPS Surveying (RTK GPS 측량에 의한 3차원 지형 해석)

  • 신상철;서철수
    • Spatial Information Research
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    • v.9 no.2
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    • pp.309-324
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    • 2001
  • To apply the real-time kinematic GPS surveying technique, this research has tried to obtain the TOKYO datum first from the continuous reference stations distributed all over the country. Then, analysis of the geography of a coastal area including both of land and sea has been carried out by the post-processed continuous kinematic GPS technique and the real-time kinematic GPS surveying technique. After considering the initial conditions and measuring time zone for real-time kinematic GPS, post-processed and the real-time kinematic GPS measurements have been carried out. A new system has been proposed to store measured data by using a program developed to store GPS data in real time and to monitor the satellite condition through controller simultaneously. The accuracy of GPS data acquired in real time was as good as that acquired by post processing. It is expected that it will be useful for the analysis of coastal geographic characteristics because DTM can be also constructed for the harbor reclamation, the dredging and the variation of soil movement in a river.

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Intraspecific sequence variation of trnL/F intergenic region (cpDNA) in Sedum takesimense Nakai (Crassulaceae) and aspects of geographic distribution (섬기린초에서 엽록체 DNA 염기서열의 종내 변이와 지리적 분포 양상 연구)

  • Lee, Woong;Pak, Jae-Hong
    • Korean Journal of Plant Taxonomy
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    • v.40 no.3
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    • pp.157-162
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    • 2010
  • Sequences of the trnL/F intergenic spacer of chloroplast DNA were used to investigate the intraspecific evoution and phylogeography of Sedum takesimense (Crassulaceae). The trnL/F intergeneric spacer sequences from 32 individuals of S. takesimense were either 291 bp (17 samples "without indel" in the following) or 297 bp (15samples "with indel 1") in length due to an indel of 6 bp. Two main cpDNA haplotypes were detected within S. takesimense. The haplotype with indel was found on Ulleung Island and without indel on Ulleung Island and Dok Island. This confirmed the existence of two cpDNA lineages with different geographical distributions. The cpDNA sequence analysis also suggested a putative long-distance dispersal event between Ulleung Island and Dok Island.

Isolation and characterization of micro satellite loci in the Korean crayfish, Cambaroides similis and application to natural population analysis

  • Ahn, Dong-Ha;Park, Mi-Hyun;Jung, Jae-Ho;Oh, Mi-Jin;Kim, Sang-Hee;Jung, Jong-Woo;Min, Gi-Sik
    • Animal cells and systems
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    • v.15 no.1
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    • pp.37-43
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    • 2011
  • The Korean freshwater crayfish, Cambaroides similis, has recently suffered from range reduction and habitat degradation caused by environmental changes and water pollution. For the conservation and restoration of this species, it is necessary to understand the current population structures of Korean C. similis using estimation of their genetic variation. In this study, eight micro satellite loci were developed and characterized from 49 individuals collected from four locations: one population from Mt. Bukhan (BH) and three populations from Mt. Gwanak (GA) in Seoul, Korea. As a result, the number of alleles per locus ranged from 2 to 12. The observed heterozygosities and expected heterozygosities ranged from 0.000 to 0.833 and from 0.125 to 0.943, respectively, and the former values were significantly lower than the latter ones expected under the Hardy-Weinberg equilibrium. No significant linkage disequilibrium was revealed between any of the locus pairs after Bonferroni correction. From the pairwise Fst results over all samples, higher differentiation between GA-BH population pairs (mean 0.1789) was observed than between GA population pairs (mean 0.0454). This was also supported by Mantel's test showing that the genetic distances of these crayfish populations were significantly correlated with geographic distances. This result may show the regional differentiation caused by restricted gene flow between northern (BH) and southern (GA) populations within Seoul. These micro satellite markers have the potential for use in analyses of the genetic diversity and population structure of C. similis species, with implications for its conservation and management plans.

Genetic Differences and Geographic Variation in Cuttle Fish (Sepia esculenta Hoyle)

  • Yoon, Jong-Man;Kim, Jong-Yeon
    • Development and Reproduction
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    • v.14 no.3
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    • pp.163-170
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    • 2010
  • The gDNA isolated from Korean cuttle fish (Sepia esculenta Hoyle) from Sockcho (SOCKCHO), Seocheon (SEOCHEON), Incheon (INCHEON) and Vietnamese cuttle fish (VIETNAM), were amplified by PCR. Here, the seven selected primers (BION-A07, BION-A09, BION-A11, BION-A20, BION-B04, BION-B06, and BION-B14) were used to generate the unique shared loci to each population and shared loci by the four cuttle fish populations. In this study, the primer BION-A11 detected 112 shared loci by the four populations, major and/or minor fragments of sizes 300 bp, 400 bp, 700 bp and 1,000 bp, respectively, which were identical in all samples. The dendrogram obtained by the seven primers indicates five genetic clusters: cluster 1 (SOCKCHO 01-SOCKCHO 07), cluster 2 (SEOCHEON 08-SEOCHEON 10), cluster 3 (SEOCHEON 11-SEOCHEON 14), cluster 4 (INCHEON 15-INCHEON 21), and cluster 5 (VIETNAM 22-VIETNAM 28). The shortest genetic distance that displayed significant molecular differences was between individuals 25 and 26 from the Vietnamese cuttle fish (0.025), while the longest genetic distance among the twenty-eight cuttle fishes that displayed significant molecular differences was between individuals SOCKCHO no. 02 and SEOCHEON no. 12 (0.640). Individual of Seocheon and Incheon cuttle populations was somewhat closely related to that of Vietnamese cuttle fish population. Even though it could not be affirmed by a single case, such a result seems to be closely connected that the Korean peninsula is subject to climate changes by global warming. In conclusion, our PCR analyses revealed a significant genetic distance among the four cuttle fish populations.

The First Measurement of Seasonal Trends in the Equatorial Ionospheric Anomaly Trough at the CHUK GNSS Site During the Solar Maximum in 2014

  • Chung, Jong-Kyun;Yoo, Sung-Moon;Lee, Wookyoung
    • Journal of Astronomy and Space Sciences
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    • v.33 no.4
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    • pp.287-293
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    • 2016
  • The equatorial region of the Earth's ionosphere exhibits large temporal variations in electron density that have significant implications on satellite signal transmissions. In this paper, the first observation results of the variations in the trough of the equatorial ionospheric anomaly at the permanent Global Navigation Satellite System (GNSS) site in Chuuk (Geographic: $7.5^{\circ}N$, $151.9^{\circ}E$; Geomagnetic: $0.4^{\circ}N$) are presented. It was found that the daytime Global Positioning System (GPS) total electron content (TEC) values vary according to the 27 day period of solar rotation, and that these trends show sharp contrast with those of summer. The amplitudes of the semi-annual anomaly were 12.4 TECU (33 %) on $19^{th}$ of March and 8.8 TECU (23 %) on $25^{th}$ of October respectively, with a yearly averaged value of 38.0 TECU. The equinoctial asymmetry at the March equinox was higher than that at the October equinox rather than the November equinox. Daily mean TEC values were higher in December than in June, which could be interpreted as annual or winter anomalies. The nighttime GPS TEC enhancements during 20:00-24:00 LT also exhibited the semi-annual variation. The pre-midnight TEC enhancement could be explained with the slow loss process of electron density that is largely produced during the daytime of equinox. However, the significant peaks around 22:00-23:00 LT at the spring equinox require other mechanisms other than the slow loss process of the electron density.

Systematic studies on the freshwater goby, Rhinogobius species (Percifromes, Gobiidae). II. BEographic distribution and taxonomic status of three color types in the Rhinogobius brunneus complex from South Korea. (밀어속(genus Rhinogobius, Gobiidae) 어류의 계통분류학적 연구II. 한국산 밀어(R. brunneus complex) 3型의 분포 및 분류학적 고찰)

  • 김종범;양서영
    • Animal Systematics, Evolution and Diversity
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    • v.12 no.4
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    • pp.331-347
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    • 1996
  • The geographic distribution and variation for Rhinogobius brunneus were surveyed by means of allozymic and morphological analyses and it was revealed that the Korean populations of R. brunneus comprise three distinct types, Type-A, Type-B, and Type-C, which show considerable differentiation to a degree of interspecific level(Rogers' S(1972): $S_{A-B}$=0.631, $S_{A-C}$=0.628, $S_{B-C}$=0.661). In addition, no evidence of gene flow among the types was found at sympatric area and it is assumed that reproductive isolation is completed. Moreover there is microhabitat segregation according to the distance from river mouth among each types and which segregation was regarded as a factor to facilitate reproductive isolating mechanism. Therefore, based on the evidence presented above, these three types of R. brunneus are considered as typical discrete species.

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Genetic Distribution Pattern of Bluegill Sunfish Lepomis macrochirus in Freshwater Ecosystems across Korea

  • Lau, Hwee Hui;Huang, Jingting;Kwan, Ye-Seul;Lee, Wan-Ok;Won, Yong-Jin
    • Animal Systematics, Evolution and Diversity
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    • v.25 no.3
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    • pp.325-329
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    • 2009
  • Lepomis macrochirus from the family Centrarchidae, commonly known as Bluegill sunfish, is an introduced freshwater fish in Korea that thrives in lakes, ponds, reservoirs and rivers. Since its introduction into Korea in 1969, Lepomis macrochirus has rapidly dispersed out and increased in number almost all over the freshwater ecosystems in Korea. Consequently this species causes a severe ecological problem, threatening native fishes due to its omnivorous foraging behaviors upon fish juveniles and many freshwater invertebrates. To address population genetic structure of L. macrochirus, 74 fish samples from 10 populations were collected and compared for their mitochondrial D-loop control region. As the result we found that the genetic diversity of L. macrochirus is extremely low such as resulting only four haplotypes with a few nucleotide differences among them. Analysis of molecular variance (AMOVA) revealed that the source of population genetic variation is largely retained in the comparisons among individuals within populations, while it is relatively low with slight significance at the highest hierarchical group. This distribution pattern differs from what is expected when biogeography is under the influence of natural geographic barriers such as mountain ranges in Korea. Instead the result is accord with the influential role of random spreading events facilitated by local people for aquaculture and fishing, and subsequent dispersals since its single point of introduction into Korea.

Automatic 3D soil model generation for southern part of the European side of Istanbul based on GIS database

  • Sisman, Rafet;Sahin, Abdurrahman;Hori, Muneo
    • Geomechanics and Engineering
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    • v.13 no.6
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    • pp.893-906
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    • 2017
  • Automatic large scale soil model generation is very critical stage for earthquake hazard simulation of urban areas. Manual model development may cause some data losses and may not be effective when there are too many data from different soil observations in a wide area. Geographic information systems (GIS) for storing and analyzing spatial data help scientists to generate better models automatically. Although the original soil observations were limited to soil profile data, the recent developments in mapping technology, interpolation methods, and remote sensing have provided advanced soil model developments. Together with advanced computational technology, it is possible to handle much larger volumes of data. The scientists may solve difficult problems of describing the spatial variation of soil. In this study, an algorithm is proposed for automatic three dimensional soil and velocity model development of southern part of the European side of Istanbul next to Sea of Marmara based on GIS data. In the proposed algorithm, firstly bedrock surface is generated from integration of geological and geophysical measurements. Then, layer surface contacts are integrated with data gathered in vertical borings, and interpolations are interpreted on sections between the borings automatically. Three dimensional underground geology model is prepared using boring data, geologic cross sections and formation base contours drawn in the light of these data. During the preparation of the model, classification studies are made based on formation models. Then, 3D velocity models are developed by using geophysical measurements such as refraction-microtremor, array microtremor and PS logging. The soil and velocity models are integrated and final soil model is obtained. All stages of this algorithm are carried out automatically in the selected urban area. The system directly reads the GIS soil data in the selected part of urban area and 3D soil model is automatically developed for large scale earthquake hazard simulation studies.

Genetic Homogeneity in the Domestic Silkworm, Bombyx, and Phylogenetic Relationship Between B. mori and the Wild Silkworm, B. mandarina Using Mitochondrial COI Gene Sequences

  • Kim, Iksoo;Bae, Jin-Sik;Sohn, Hung-Dae;Kang, Phil-Don;Ryu, Kang-Sun;Sohn, Bong-Hee;Jeong, Won-Bok;Jin, Byung-Rae
    • International Journal of Industrial Entomology and Biomaterials
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    • v.1 no.1
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    • pp.9-17
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    • 2000
  • Genetic variation in the domestic silkworm strains (Bombyx mori) and phylogenetic relationships between domestic silkworms and wild silkworms (B. mandarina) were investigated by using a portion of mitochondrial CGI gene sequences. Ten geographic strains of B. mori we sequenced were identical in the 410 bp-section of mitochondrial COI gene. This sequence was also identical to the homologous sequence of the four Gen-Bank-registered strains, but one strain of B. mori differed a single nucleotide (0.2%) from others. MtDNA homogeneity in the B. mori strains appears to be resulted from fixation into the mast frequent mtDNA type during the course of breeding for new strains, in which an extensive indoor rearing and removal of unwanted individuals were accompanied. In the comparisons between domestic and wild silkworms, some wild silkworms were closely related to domestic silkworms (0.2%-1.2% of divergence), but the others were not (2.7%-3.7% of sequence divergence). This result was also reflected in the phylogenetic analyses, showing two independent phylogenetic groups: one including all B. mandarina sequences and the other including both B. mandarina and B. mori sequences. Thus, domestic silkworms may have been derived from the ancestor of B. mandarina, which belongs to this group, alto-ough more extensive study will provide better understanding on this issue.

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Systematic Studies on Korean Rodents: VI. Analysis of Morphometric Characters, Chromosomal Karyotypes and Mitochondrial DNA in Two Species of Genus Rattus (한국에 서식하고 있는 설치류의 계통분류학적 연구: 6. 집쥐속 2종의 형태학적 형질, 염색체 핵형 및 미토콘디리아 DNA의 분석)

  • 고홍선
    • Animal Systematics, Evolution and Diversity
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    • v.8 no.2
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    • pp.231-242
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    • 1992
  • Samples of two species of genus Ratts(black rat, Rattus rasttus Linnaeus; common rat, Rattus norvegicus Berkenhaut) in Korea were trapped and their 31 morphometric charcters were analyzed statistically in order to determine the range of geographic variation within each species and the interspecific differences. In addition, chromosomal G-bands and C-bands were compared and the fragment patterns of mtDNA resulted from the digestion with restriction enzymes were also analyzed. Samples of black rats from six localities in Korea were similar with one another in their morphometric characters: in head and body length, length of tail vertebrae, conventional karyotype and C-bands, they are comparable to Rattus rattus tanezumi in Japan. Specimens of common rats from seven localities in Korea were similar with one another in their morphometric characters: in conventional karyotype, they are comparable to Rattus norvegicus caraco in eastern Asia. Common rats differ from black rats in their morphometric characteris, chromosomal karyotypes and mtDNA. It is confirmed that correct species name of black rat in Korea is Rattus rattus tanezumi Tempminck: species name of common rat in Korea is Rattus norvegicus caraco Pallas: the common rat is a species, which is distinct from the black rat.

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