• The Korean Journal of Ecology
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• v.28 no.6
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• pp.375-382
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• 2005

The American bullfrog, Rana catesbeiana was imported from Japan for farming for the human consumption in 1970's and introduced populations were a great threat to native habitats in the pond and lake ecosystem. However, it is thought that the population of bullfrog has rapidly declined for past years in Korea. In this study, we investigated the intra-genetic diversity of R. catesbeiana habitated in Korea. The nucleotide sequences of 1,215bp mitochondrial ND1/tRNA region in bullfrogs sampled from 5 sites in Jeollanamdo were analyzed and compared to the original sequence of R. catesbeiara reported in Genbank. The nucleotide similarity between Korean and North American bullfrog was ranged from 98.7% to 100% based on kimura-2-parameter distance. In addition, bullfrogs analyzed in this study were clustered into two groups with one including Jangheung and the other including Gwangju populations in the neighbor-joining tree. North American R. catesbeiana was grouped in Jangheung cluster, indicating that there is the very low genetic difference between Korean and North American populations. The maximum parsimony tree in which North American R. catesbeiana was set as an outgroup suggests that Jangheung group represents the introduced population to Korea. Taken together, the results indicate that the population of R. catesbeiana in Korea has not segregated geographically yet, after the introduction.

• Journal of Aquaculture
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• v.9 no.3
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• pp.287-291
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• 1996

[ $F_2$ ] generation of gynogenetic diploids were produced in olive flounder, Paralichthys olivaceus, by brother-sister mating with full-sibling gynogenetic diploids ($F_1$). The induced ovulations and spawnings were conducted by using intraperitoneal injections of HCG (2,000 IU/kg body weight) with photoperiod controls. Floating rates of artificially ovulated eggs were ranged from 22.9 to $65.7\%$. Fertilization and hatching rates were ranged from 69.0 to $86.2\%$ and 36.8 to $85.8\%$, respectively. All of those three rates between two experimental groups were not significantly different (P>0.05). Average survival rates of $F_2$ generation of 40-day-old 효nogenetic diploid larvae were slightly lower than those of controls (P<0.05), however growth rates were much higher than those of their diploid controls.

• Journal of Aquaculture
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• v.21 no.1
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• pp.13-18
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• 2008

Marine birnavirus(MABV) are well known fish pathogens in Asian countries such as Korea, Japan, and China. Prevalence of viral disease, geological distribution and host or reservoir of viruses were investigated from wild marine fishes in southern coast of Korea in 2003 and 2005. RT-PCR results showed that MABV were detected in 17 fishes(10.6%) from 160 fishes. Comparative analysis of the nucleotide sequences and the deduced amino acids of MABV genome from wild fishes were similar to reference strains of MABV and distinguished with IPNV strains.

• Journal of Aquaculture
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• v.6 no.3
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• pp.221-233
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• 1993

Cell size, DNA content, chromosome and PCR-based mitochondrial 12S rRNA gene analyses were conducted to obtain basic informations for genetic stock identification of spotted flounder (Verasper variegatus) from Yeocheun, Korea. The mean erythrocytic and nuclear volumes of spotted flounder were $211.10{\mu}m^3$ and $23.03{\mu}m^3$, respectively. The haploid DNA content of this species was 0.79 pg/cell which correspond to $46.5\%$ of carp and to $22.6\%$ of mammals. Spotted flounder had the 2n = 46 acrocentric chromosomes but no heteromorphic sex chromosomes was found. Mitochondrial DNA gene for 12S ribosomal RNA was amplified by polymerase chain reaction (PCR) and the PCR products were subjected to digestion with 15 restriction endonucleases. Restriction enzyme analyses revealed that Ava I, Mae II, Sma I and Xba I had one restriction site in the mitochondrial 12S rRNA gene segment of spotted flounder, while Mae I had two. Segments of 12S rRNA gene from mitochondria in spotted flounder were sequenced and compared with channel catfish and human as controls. The 12S rRNA gene of this species was more similar to that of channel catfish than to human's.

• Journal of Aquaculture
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• v.11 no.3
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• pp.353-361
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• 1998

Genetic analysis of body pigmentation pattern has been conducted by the reciprocal monohybrid and back crosses using the wild type zebrafish, Danio rerio, and its aquarium morphs (mutants), leopard danio. Also, the effect fo pigmentation mutation was investigated with regard to the survival rates of eggs and larvae for the first 15 days after fertilization. As a result, the pattern pigment distribution was inherited by a single gene having two alleles, and which was basically followed by the principle of dominace and segregaion in Mendelian inheritance. A locus for pigment pattern turned out to be located on an autosomal chromosome. Average survival rates estimated from the various crosses between, and within, wild type zebrafish and leopard danio were as follows ; they were 80.6${\pm}$4.8% from the crosses within leopard danios ($L{\times}L$), 70.6${\pm}$4.2% between leopard female and wild type male ($L{\times}Z$), 73.2${\pm}$2.0% between wild type female and leopard male ($Z{\times}L$), and 83.8${\pm}$6.7% within wild type zebrafish ($Z{\times}Z$). These results indicated that the leopard danio, which were reported as an "aquarium morph" several decades ago and also known as a mutant in pigmentation pattern of the wild type zebrafish, seemed to be genetically stable like the wild type of zebrafish.zebrafish.

• Journal of Aquaculture
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• v.20 no.2
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• pp.140-143
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• 2007

Cytogenetic analyses of an endemic species, Coreoleuciscus splendidus (Cyprinidae) was performed including erythrocyte measurement, chromosome count and karyotyping, nucleolar organizing region (NOR) banding and flow cytometric analysis of genome size. C. splendidus had the same modal chromosome number of 2n = 48 between sexes, however, displayed a sex-related dimorphism in their chromosome karyotypes. Males represented a pair of heteromorphic chromosomes which couldn‘t be seen in any female individuals, indicating that the sex determination mechanism of this species should be a typical XX-XY based male heterogamety (female=10M+6SM+8A+XX vs male=10M+6SM+8A+XY). Other cytogenetic features such as Ag-NORs located in a pair of acrocentric chromosomes, estimated nuclear volume ($28{\mu}m^3$) and cellular DNA content (2.4 pg/cell) suggest that genetic recombination might be the main driving force responsible for the evolution of this species rather than the polyploidy-based evolutionary process as in many other Cyprinidae species.

• Journal of Aquaculture
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• v.19 no.3
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• pp.166-172
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• 2006

Induced androgenesis, a form of artificial parthenogenesis is an important tool for the generation and use of genetically isogenic or clonal fish strain. An optimized protocol for the genetic inactivation of mud loach (Misgurnus mizolepis) oocytes (i.e. production of androgenetic haploid) was developed using UV-irradiation. Various dose levels of UV significantly affected the fertilizing capacity of the eggs, hatchability of embryos and incidence of haploidy. Based on the extensive examinations of treatment conditions on embryo viability and haploid incidence, the optimum dose level of UV irradiation was turned out to be $10,800ergs/mm^2$ with 56.9% of hatching success and 94.6% of haploidy. The overall yield of putative androgen under optimized treatment condition was more than 50% out of total eggs inseminated. The success of androgenetic reproduction of haploid genome was verified by flow cytometry and PCR amplification of transgene that is exclusive to either one of parental sexes. However, a small portion $(8\sim11%)$ of presumed androgenetic haploid larvae was proven to contain residual DNA fragment(s) from maternal parent.

• Journal of Life Science
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• v.22 no.4
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• pp.466-471
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• 2012

Sixty individuals of the scallop $Patinopecten$ $yessoensis$ (Genus Pecten) were sampled to examine the genetic diversity and population structure of this species. Random amplified polymorphic DNA (RAPD) identified 109 genotypes and produced 79 polymorphic loci (72.8%). Total genetic diversity values ($H_T$) and interlocus variation in the within-population genetic diversity ($H_S$) were 0.254 and 0.178, respectively. On a per-locus basis, the proportion of total genetic variation due to differences among populations ($G_{ST}$) was 0.299. This indicated that about 70.1% of the total variation was within populations. The unique loci and bands of $P.$ $yessoensis$ were shown in only one population among the three countries. RAPD markers were very effective in classifying the natural population levels of $P.$ $yessoensis$ in Korea, China, and Japan. In addition, insights into the relative gene diversity among and within populations of $P.$ $yessoensis$ would be useful in breeding and for the development of strategies for animal genetic resources.

• The Korean Journal of Applied Statistics
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• v.21 no.1
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• pp.81-94
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• 2008

Family-based tests such as the transmission and disequilibrium tests(TDT) have proved to be powerful tools in the search for disease genes. Unlike case-control studies, the tests are not affected by population admixture, which can lead to spurious association of multiple highly linked makers with disease-susceptible genes. Those tests have largely required knowledge of parental marker genotypes. However, parental data are often not available for late-onset diseases. In this article we propose sib-TDTs that overcome this problem by use of marker data from unaffected sib(s) instead of parents. To do this end, we fist defined a Mantel-Haenszel-type statistic for each haplotype and then proposed two tests based on this statistic. Simulation studies suggest that the proposed tests are robust to population admixture and are monotone increasing as a relative risk increases irrespective of mode of inheritance. We also illustrated the proposed tests with data adopted from Yonsei Cardiovascular Genome Center.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.2
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• pp.208-214
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• 1987

A genetic study on the panicle characters in Oryza sativa was carried out by means of a 5 x 5 diallel cross. The five parental varieties were Raekyung, Yeongnamjosaeng, Nongbaek, Yushin and Honenwase. All characters were correlated positively each other, except number of kernels per primary branch. The number of secondary branches per primary branch.was the most effective factor in determining the number of kernels per panicle, the next being the number of primary branches per panicle. Regression analyses of the data of Vr/Wr indicated the presence of non-allelic gene interactions for all characters. Overdominant characters were the number of kernels per panicle, the number of primary branches per panicle, the number of secondary branches per primary branch, the number of kernels per primary branch and sum of kernels on all the tertiary branches per panicle, suggesting that the characters were more influenced by dominant effect than additive effect. However, the number of kernels per secondary branch was partially dominant where the genetic variation was due more to additive effect than to dominance effect. But after omitting the parent which had non-allelic interaction gene, the characters; the number of kernels per panicle, the number of secondary branches per primary branch, and the number of kernels per secondary branch, were partially dominant. Narrow sense heritabilities(h$^2$ N) in number of kernels per panicle and number of secondary branches were high and moderate, respectively, but those of the rest were lower. Mean squares of GCA and SCA of all characters, except SCA of the number of kernels per secondary branch, were highly significant. Effects of GCA were larger than SCA effects in all characters. Raekyung, Yushin and Nongbaek had highly positive GCA, and the best positive SCA was observed in crosses of Nongbaek x Tongillines (Raekyung, Yushin, and Yeongnamjosaeng) in all characters.