• Title/Summary/Keyword: population genetics

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ON THE DIFFUSION PROCESSES AND THEIR APPLICATIONS IN POPULATION GENETICS

  • Choi, Won;Lee, Byung-Kwon
    • Journal of applied mathematics & informatics
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    • v.15 no.1_2
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    • pp.415-423
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    • 2004
  • In allelic model X = ($x_1,\;x_2,...x_{d}$), $M_f(t)$= f(p(t)) - ${{\int}^{t}}_0$Lf(p(t))ds is a P-martingale for diffusion operator L under the certain conditions. In this note, we can show uniqueness of martingale problem associated with mean vector and obtain a complete description of ergodic property by using of the semigroup method.

ON THE LIMITING DIFFUSION OF SPECIAL DIPLOID MODEL IN POPULATION GENETICS

  • CHOI, WON
    • Bulletin of the Korean Mathematical Society
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    • v.42 no.2
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    • pp.397-404
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    • 2005
  • In this note, we characterize the limiting diffusion of a diploid model by defining the discrete generator for the resealed Markov chain. We conclude that this limiting diffusion model is with uncountable state space and mutation selection and special 'mutation or gene conversion rate'.

ON THE MARTINGALE PROBLEM AND SYMMETRIC DIFFUSION IN POPULATION GENETICS

  • Choi, Won;Joung, Yoo-Jung
    • Journal of applied mathematics & informatics
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    • v.28 no.3_4
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    • pp.1003-1008
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    • 2010
  • In allelic model $X\;=\;(x_1,\;x_2,\;\cdots,\;x_d)$, $$M_f(t)\;=\;f(p(t))\;-\;\int_0^t\;Lf(p(t))ds$$ is a P-martingale for diffusion operator L under the certain conditions. In this note, we define $T_tf\;=\;E_{p_0}^{p^*}\;[f((P(t))]$ for $t\;{\geq}\;0$ for using a new diffusion operator $L^*$ and we show the diffusion relations between $T_t$ and diffusion operator $L^*$.

SOME SYMMETRY PRESERVING TRANSFORMATION IN POPULATION GENETICS

  • Choi, Won
    • Journal of applied mathematics & informatics
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    • v.27 no.3_4
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    • pp.757-762
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    • 2009
  • In allelic model $X\;=\;(x_1,\;x_2,\;{\cdots},\;x_d)$, $$M_f(t)\;=\;f(p(t))\;-\;{\int}^t_0\;Lf(p(t))ds$$ is a P-martingale for diffusion operator L under the certain conditions. We can also obtain a new diffusion operator $L^*$ for diffusion coefficient and we prove that unique solution for $L^*$-martingale problem exists. In this note, we define new symmetric preserving transformation. Uniqueness for martingale problem and symmetric property will be proved.

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Neutron clustering in Monte Carlo iterated-source calculations

  • Sutton, Thomas M.;Mittal, Anudha
    • Nuclear Engineering and Technology
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    • v.49 no.6
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    • pp.1211-1218
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    • 2017
  • Monte Carlo neutron transport codes generally use the method of successive generations to converge the fission source distribution to-and then maintain it at-the fundamental mode. Recently, a phenomenon called "clustering" has been noted, which produces fission distributions that are very far from the fundamental mode. In this study, a mathematical model of clustering in Monte Carlo has been developed. The model draws on previous work for continuous-time birth-death processes, as well as methods from the field of population genetics.

Genetic Diversity and Differentiation in Remnant Populations of Bupleurum latissimum Nakai, an Endangered Endemic Plant Species to Ulleung Island, Korea

  • Ku, Youn-Bong;Oh, Hyun-Kyung;Kong, Hak-Yang;Suh, Min-Hwan;Lee, Min-Hyo;Sviatlana, Trybush;Cho, Kang-Hyun
    • 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.

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.

Geographic Genetic Contour of a Ground Beetle, Scarites aterrimus (Coleoptera: Carabidae) on the Basis of Mitochondrial DNA Sequence

  • Wang, Ah-Rha;Kim, Min-Jee;Cho, Young-Bok;Wan, Xinlong;Kim, Ik-Soo
    • International Journal of Industrial Entomology and Biomaterials
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    • v.22 no.2
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    • pp.65-74
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    • 2011
  • The Scarites aterrimus (Coleoptera: Carabidae), is one of the carabid beetles dwelling exclusively on coastal sandy dunes. Habitat deterioration and equivalent activity have greatly concerned population declines in several species dwelling on the coastal sandy dunes. As a first step to establish long-term conservation strategy, we investigated the nation-wide magnitude and nature of genetic diversity of the species. As a first step, we sequenced a portion of mitochondrial COI gene, corresponding to "DNA Barcode" region (658 bp) from a total of 24 S. aterrimus individuals collected over nine sandy dunes belonging to four Korean provinces. The sequence analysis evidenced moderate to low magnitude of sequence diversity compared with other insect species distributed in Korean peninsula (0.152% to 0.912%). The presence of closely related haplotypes and relatively high gene flow estimate collectively suggest that there had been no historical barriers that bolster genetic subdivision. Population decline was postulated on the basis of several missing haplotypes that are well found in the species with a large population size. This interpretation is consistent with field observation of small population size in the coastal sandy dune habitats. The highest genetic diversity estimates were found in the coastal sand dune population of Seogwipo, Jeju Island, justifying a prior attention to the population, in order to sustain overall genetic diversity of the species. Further scrutinized study might be required for further robust conclusion.

A Pursuit of Innovation in the Korean Genetics-Genomics Research System through a Culturalist Strategy (문화적 전략을 통한 한국 유전학-유전체학 연구체계의 혁신 모색)

  • Lee, Cheong-Ho
    • Journal of Science and Technology Studies
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    • v.6 no.2 s.12
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    • pp.131-183
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    • 2006
  • The Korean genetics and genomics reveal a firm willingness to participate in and contribute to the production of creative scientific knowledge at a world level at present, though they have short past histories of introduction from the Western counterparts and those of education for the next generations. But the Korean genetics and genomics have been developed in a fragmented and biased manner. By reconfiguring the various research projects of genomics into the Genome Project of Korea, which reflect a worldly trend in life science, but have been established in a scattered fashion in Korea, and incorporating some neglected areas of genetics, such as human genetics and theoretical and population genetics which can be reconstructed in a new way, a genetics-genomics research system can be formulated on the multi-tiered perspective of concept, knowledge, and institution, while the system being a subsystem of the national research system of life science in Korea. Innovation can be pursued in the systematic practice through a culturalist strategy. The culturalist strategy with the practice based on the research system consists of 1) intensification of fundamentalness of genetics and genomics, 2) advancement of communitarianism in geneticist-genomicist community, 3) research on the cultural bio-species along with the promotion of scientific arts and culture, and 4)formation of the Korean science studies of genetics-genomics and the diffusion of the knowledge produced. The first two strategy components are the ones that intends to bring out changes in the structural aspect of the scientist community in Korea. The third is the one that attempts to magnify the interface between the scientist community and the Korean society at large and increase its connectivity between both, while the fourth is the one that has an intentionality toward the Korean society outside of the scientist community. This culturalist strategy is intended to increase the cultural constructivity of the genetics-genomics research system in Korea.

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