• Development and Reproduction
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• v.12 no.2
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• pp.151-158
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• 2008

The variability within and between Korean pond-smelt (Hypomesus nipponensis; KPS) and Canadian capelin (Mallotus villosus; CCP) were studied in order to clarify the genetic distances and differences. The dendrogram obtained by the seven primers indicates cluster 1 (KOREAN 01$\sim$KOREAN 11) and cluster 2 (CANADIAN 12$\sim$CANADIAN 22). The longest genetic distance displaying significant molecular differences was found to exist between individuals in the two geographic species of Osmeridae, between individuals' no. 10 of Korean and no. 18 of Canadian (0.686). 121 unique shared loci to each species, with an average of 17.3 per primer, were observed in the KPS species, and 264 loci, with an average of 37.7 per primer, were observed in the CCP species. 77 shared loci by the two species, with an average of 11.0 per primer, were observed in the two fish species. RAPD analysis showed that the KPS species was more genetically diverse than the CCP species. KPS species may have high levels of genomic DNA variability owing to the introduction of the wild individuals from the other sites to sampling sites although it may be the geographically diverse distribution of this species. As stated above, the existence of species discrimination and genetic variability between the KPS and the CCP species was identified by RAPD analysis.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.11
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• pp.1631-1635
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• 2007

Japanese Brown cattle, one of the four domestic beef breeds in Japan, are suffering from numerical reduction due to economic pressure from profitable breeds. In this study, all the reproductive cows in the Kouchi sub-breed of the Japanese Brown cattle that were alive in July 2005 were investigated by pedigree analysis to clarify genetic structure and composition of genetic variability. In addition, genetically important individuals for the maintenance of genetic variability of the sub-breed were also identified through the core set method. The number of cows analyzed was 1,349. Their pedigrees were traced back to ancestors born around 1940, and pedigree records of 13,157 animals were used for the analysis. Principal component analysis was performed on the relationship matrix of the cows, and their factor loadings were plotted on a three-dimensional diagram. According to their spatial positions in the diagram, all the cows were subdivided into five genetically distinctive subpopulations of 131 to 437 animals. Genetic diversity of the whole sub-breed, which is estimated to be 0.901, was decomposed into 0.856 and 0.045 of within-subpopulation and between-subpopulation components. Recalculation of genetic diversity after removal of one or several subpopulations from the five subpopulations suggested that three of them were genetically important for the maintenance of genetic variability of the sub-breed. Applying the core set method to all the cows, maximum attainable genetic diversity was estimated to be 0.949, and optimal genetic contributions assigned to each cow supported the previous results indicating relative importance of the three subpopulations as useful genetic materials.

• Animal cells and systems
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• v.9 no.1
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• pp.27-35
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• 2005

Bupleurum euphorbioides is isolated and restricted to high mountains in Korea northeastern China. Its conservation depends on whether it is threatened by inbreeding or a loss of genetic diversity. We compared the genetic variability in B. euphorbioides with B. longiradiatum, a widespread congener, to understand how they differ in their population genetic structure. Although B. euphorbioides showed a little lower genetic variability than B. longiradiatum, $F_{IS}$ statistics for most loci were strongly positive in both B. euphorbioides (0.445) and B. longiradiatum (0.553). In addition, B. euphorbioides showed higher mean $F_{ST}$ value than B. longiradiatum (0.297 vs 0.194). It might be due to the polycarpic nature of B. longiradiatum, which holds higher genetic potentials effectively in homogeneous environment than the monocarpic B. euphorbioides. The results suggested that B. euphorbioides is a genetically viable species, and that they are threatened primarily by environmental factor.

• Journal of Korean Institute of Industrial Engineers
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• v.43 no.3
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• pp.164-175
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• 2017

Dual response surface optimization (DRSO) attempts to optimize mean and variability of a process response variable using a response surface methodology. In general, mean and variability of the response variable are often in conflict. In such a case, the process engineer need to understand the tradeoffs between the mean and variability in order to obtain a satisfactory solution. Recently, a Posterior preference articulation approach to DRSO (P-DRSO) has been proposed. P-DRSO generates a number of non-dominated solutions and allows the process engineer to select the most preferred solution. By observing the non-dominated solutions, the DM can explore and better understand the trade-offs between the mean and variability. However, the non-dominated solutions generated by the existing P-DRSO is often incomprehensive and unevenly distributed which limits the practicability of the method. In this regard, we propose a modified P-DRSO using multiple objective genetic algorithms. The proposed method has an advantage in that it generates comprehensive and evenly distributed non-dominated solutions.

• Plant Biotechnology Reports
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• v.2 no.3
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• pp.191-198
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• 2008

Germplasm characterization and evolutionary process in viable populations are important links between the conservation and utilization of plant genetic resources. Here, an investigation is made, based on molecular and biochemical techniques for assessing and exploiting the genetic variability in germplasm characterization of taro, which would be useful in plant breeding and ex situ conservation of taro plant genetic resources. Geographical differentiation and phylogenetic relationships of Indian taro, Colocasia esculenta (L.) Schott, were analyzed by random amplified polymorphic DNA (RAPD) and isozyme of seven enzyme systems with specific reference to the Muktakeshi accession, which has been to be proved resistant to taro leaf blight caused by P. colocasiae. The significant differentiations in Indian taro cultivars were clearly demonstrated by RAPD and isozyme analysis. RAPD markers showed higher values for genetic differentiation among taro cultivars and lower coefficient of variation than those obtained from isozymes. Genetic differentiation was evident in the taro accessions collected from different regions of India. It appears that when taro cultivation was introduced to a new area, only a small fraction of genetic variability in heterogeneous taro populations was transferred, possibly causing random differentiation among locally adapted taro populations. The selected primers will be useful for future genetic analysis and provide taro breeders with a genetic basis for selection of parents for crop improvement. Polymorphic markers identified in the DNA fingerprinting study will be useful for screening a segregating population, which is being generated in our laboratory aimed at developing a taro genetic linkage map.

• Journal of Sericultural and Entomological Science
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• v.39 no.2
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• pp.119-133
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• 1997

Isozyme was used to characterize general protein patterns of genetic relationships among 303 silkworm stocks preserved in National Sericultural and Entomology Research Institute, RDA. Six isozymes (esterase, acid phosphatase, alkaline phosphatase, amylase, glucose-6-phosphate dehydrogenase and sucrase) from hemolymph, midgut, and digestive juice were employed to construct dendograms(UPGMA method) using a polycrylamide gel electrophoresis. A cluster analysis revealed four major group, which were divided into several subgroups within each group, contained assemglages of Japanese and Chinese races. Especially, genetic differentiation in the first and second group was greatest rather than within Japanese and Chinese races repectively and was concordant with the hypothesis of phyletic sorting of initial variability in China many years ago. Hypothesized recent introgression between groups was also plausible, but the eviednce suggested bidirectional gene flow between the Chinese and the Japnaese lineages. Interpreting the results in light of evidence from the current study, the genetic diversity and relationship showed in Korean silkworm race, Hansammyun reflected early and independent evolution from the Chinese ancestor, limited addition of new variability and phyletic sorting within Korean peninsula more than 4,000 years.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.6
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• pp.747-753
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• 2001

In this study, the Italian milk recorded buffalo population from 1974 to 1996 was analysed with the purpose to estimate genetic and environmental variability and provide genetic parameters for the most important economic traits. High variability between herds was evident due to the poor knowledge of feeding requirements and husbandry technology in this species compared to cattle. Age at first calving was reduced by 57 days during the considered years following efforts made in better feeding and management from 1990; on the contrary, calving interval has increased by 17 days as a consequence of forcing buffaloes to calve in spring, in order to have the peak milk yield when milk is much better paid. Average milk yield increased by 1853 kg during these years, while lactation duration was reduced by 30 days. Season of calving has no effect on all traits. Calving order has a positive effect on milk yield especially because older cows produce more milk in shorter lactations. Heritability for the age at first calving and calving interval was 0.26 and 0.05 respectively. Heritability of productive traits, milk yield and duration of the lactation was 0.19 and 0.13 respectively, with repeatabilities of 0.40 and 0.26. Genetic trend for milk yield was 2.1 kg milk/year for the bulls and 1 kg for all population. The high genetic variability of milk production as well as duration of the lactation, indicates that there are good opportunities for genetic improvement when including these traits in a selection scheme. The low genetic trend registered over 15 years of recording activity can be explained by the fact that neither progeny testing was performed or selection schemes were implemented, due to the difficulties to use artificial insemination in buffalo.

• Fisheries and Aquatic Sciences
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• v.11 no.2
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• pp.82-87
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• 2008

Marine fisheries are important natural resources and must be maintained, especially fish species that are important sources of food. Despite the increase in stocking programs to maintain fisheries with artificially raised fish, the genetic impact stocking has on the wild fry population has not been addressed. Genetic variation in rock bream, Oplegnathus fasciatus, within and between wild-caught parents and the $F_1$ generation produced by them in 1 day was assayed using nine highly variable micro satellite markers. The nine micro satellite loci used in this study displayed diverse polymorphisms, and in total, 98 different alleles were observed over all loci. Differences in genetic variability of the $F_1$ offspring compared to their wild-caught parents (brood stock) were observed in terms of allele frequency, gene diversity, and heterozygosity. Although the $F_1$ generation of rock bream was missing 16% of the micro satellite alleles, no significant reduction was found in mean heterozygosity of the $F_1$ population compared to the brood stock. Eight of nine loci showed significant Hardy-Weinberg equilibrium (HWE) deviations in the $F_1$ population, while the brood stock deviated from HWE at three micro satellite loci (KOF85, KOF360 and KOF374). These deviations showed mostly a deficit of heterozygotes. Our results provide evidence for genetic differences in the $F_1$ hatchery offspring compared to their wild-caught parents and reinforce the need for a series of consecutive egg collections to avoid the loss of genetic variability. This also further underscores the importance of monitoring genetic variability of hatchery populations for the conservation of natural rock bream resources.

• The Plant Pathology Journal
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• v.25 no.3
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• pp.236-240
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• 2009

Tylenchulus semipenetrans, citrus nematode is an important phytopathogenic nematode and responsible for serious damage on citrus. However, little information is available about genetic variability of T. semipenetrans among different populations with variation of conventional diagnostic characteristics. In this study, we compared the morphometric and genetic characteristics among different populations. The mature female of T. semipenetrans collected in this study had thicker cuticle than those in the previous studies. In comparative sequence analysis of T. semipenetrans populations obtained from Jeju in Korea, we observed genetic variations within clones generated from single individuals. To determine whether variability among copies of nuclear ribosomal DNA sequences exists in the genome of T. semipenetrans, PCR-RFLP technique from individuals of Korean isolates with MseI and MspI restriction enzymes was used to prove experimentally that all populations have intra-specific variations. Restriction enzyme digestion created several fragments on 3.0% agarose gel corresponding to several haplotypes in all populations, though some populations displayed fragment deletion. The total length of fragments was larger than before digestion, indicating sequence heterogeneity within the genome of T. semipenetrans.

• Journal of Life Science
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• v.9 no.1
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• pp.14-16
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• 1999

Genetic variability was monitored by random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) in dicofol-susceptible (S), dicofol-resistant (R) and its reverse-selected (RS) strains of two-spotted spider mite, of Tetranychus urticae. Before the reverse-selection, RS strain, selected reversely from R strain, was 23-fold resistance ratio at {TEX}$LC_{50}${/TEX} to S strain. The resistance was started to in incline slowly to the resistance level of S strain after one year, and the resistance ratio was 4-fold in the 7 years after then. PCR-amplification of T. urticae DNA showed polymorphism in the amplifications with 12 primers in 100 kinds of arbitrary DNA sequences. RAPD amplification with primer OPR-12 (5`-ACAGGTGCGT-3`) showed amplified bands at 1,000 base pair in the S-and RS-strain, and at 350 base pair in R-strain. The results of polymorphism are genetic variabilities derived from development and selection of resistance in each strain. The peculiarly amplified fragments were guessed to participate in dicofol resistance. From the analysis of genetic similarity, it is inferred the gene composition of S-and RS-strain is much closer than that of R-strain.