• Journal of Sericultural and Entomological Science
• /
• v.37 no.1
• /
• pp.10-15
• /
• 1995

Genetic characterization of Sri Lankan silkworm bivoltine population has not been at-tempted so far, since its sporadic introduction of bivoltine strains into the island, starting from the 1950's. Genetic structure of Sri Lankan population of mulberry silkworm Bombyx mori was investigated through estimation of general (GCA) and specific combining ability(SCA) and heritability(${h^2}_B$), on the economic quantitative characters from leading 8 inbreds and their 28 F1's in a half diallel cross, in an attempt to utilize the estimates in determination of future breeding methods and to predict the breeding value over the phenotypic value. It was found that the breeding population of the bivoltine silkworm in Sri Lanka has still maintained considerable amounts of additive gene action as well as nonadditive. For some time in the future, both breeding strategies of "selection without inbreeding" and also "inbreeding followed by crossing" should therefore be effective in genetic improvement of economic characters investigated. In addition, superior combiners in general and in specific F1′s were identified for each of 6 economic characters, to be immediately utilized in selection and also in cross breeding programs in Sri Lanka.

• Korean System Dynamics Review
• /
• v.4 no.2
• /
• pp.71-94
• /
• 2003

The purpose of this dissertation is to build a development density control model and estimate optimum developmental density level for a sustainable urban growth management. To develop the model, system dynamics modeling approach was used. The model was developed to analyze how urban growth, transition, and decay occur depending on the interaction among population, houses, industry structure, land and urban infrastructure such as road, water supply, and sewage treatment facilities. The model was applied to Anyang city to estimate optimum density level. Extensive computer simulation was conducted to find out the maximum numbers of population, industry structure, houses, and cars that can be adequately sustained with the current Anyang city's infrastructure capacity. The computer simulation result shows that the city is overpopulated by some 90,000 people. It nab analyzed that 20％ increase of existing capacity of urban infrastructure is necessary to support current population of Anyang city. To reduce the population to the adequate level whereby the current urban infrastructure can sustain, the current city regulation on floor area ratio needs be strengthened at least 20％ to 35%.

• Korean Journal of Agricultural Science
• /
• v.42 no.4
• /
• pp.397-406
• /
• 2015

Quantitative traits are mostly controlled by a large number of genes. Some of these genes tend to have a large effect on quantitative traits in cattle and are known as major genes primarily located at quantitative trait loci (QTL). The genetic merit of animals can be estimated by genomic selection, which uses genome-wide SNP panels and statistical methods that capture the effects of large numbers of SNPs simultaneously. In practice, the accuracy of genomic predictions will depend on the size and structure of reference and training population, the effective population size, the density of marker and the genetic architecture of the traits such as number of loci affecting the traits and distribution of their effects. In this review, we focus on the structure of Hanwoo reference and training population in terms of accuracy of genomic prediction and we then discuss of genetic architecture of intramuscular fat(IMF) and marbling score(MS) to estimate genomic breeding value in real small size of reference population.

• Journal of Ecology and Environment
• /
• v.48 no.1
• /
• pp.49-59
• /
• 2024

Background: The present study aims to identify the pattern and size of Juniperus species (Juniperus phoenicea and J. procera) in the natural forests in terms of tree dimension, size structure and density, discussing the existing both species in Sarrawat Mountains for suggesting the preservation, conservation, and sustainable development. For achieving this, the height and mean crown diameter of each individual was measured based on 2-4 diameter measurements per ind. (506 ind. for J. phoenicea and 322 ind. for J. procera). Results: The size index of both species was classified into 7 classes: the first (< 100 cm) and the second (100-200 cm) classes were chosen to represent the juvenile stage. The total mean of the J. phoenicea population increased with the increase of altitude, while the whole population decreased after altitude of 2,000 m. The total mean of the J. procera population increased with the increase of altitude till altitude of 2,000-2,100 m. Conclusions: The present study indicated that both of species grow at low altitudes, they only grow at altitude above 1,700 m above sea level. The present study indicated that the study area has the two Juniperus spp. (J. phoenicea and J. procera) associated together all over the area. The results were discussed and compared with other related studies.

• Journal of Life Science
• /
• v.19 no.2
• /
• pp.174-178
• /
• 2009

The characteristics of the population genetic structure of the Japanese anchovy (Engraulis japonicus Temminck & Schlegel) were collected from the West, South and East Seas of Korea in August, 2006 and were compared using six microsatellite DNA loci. In the West Sea population, the range of allele number against 72 individuals was from 19 to 41, the average allele number was 28.5. In EJ9, the allele number had the highest value of 41, this was 1.4 times higher than the average number of allele. The average allele number of the South Sea population was 24.5 that was less than that of West Sea population. In EJ2, EJ9 and EJ27.1 loci, the allele number was higher than average allele number in the South Sea population. In the East Sea population, the average allele number was estimated at 25.0 that most of loci except for EJ35 were higher than average allele number. Allele frequency in the West, South and East Sea populations was below 0.24. The value of observed heterozosity for six loci was approximately 0.5 higher than that of expected heterozosity (p>0.05), but three populations similar values to these heterozosity. Although the genetic diversity was higher value of above 0.9, three populations had a similar value. Genetic differentiation and distance combined estimate of the six loci were 0.258 and 0.019 (p>0.05), respectively, but showed no significant distance between three populations. These results suggested that it is responsible for no differentiated gene pool between three populations.

• Animal Bioscience
• /
• v.34 no.7
• /
• pp.1105-1115
• /
• 2021

Objective: To conserve and utilize the genetic resources of a traditional Chinese indigenous pig breed, Liangshan pig, we assessed the genetic diversity, genetic structure, and genetic distance in this study. Methods: We used 50K single nucleotide polymorphism (SNP) chip for SNP detection of 139 individuals in the Liangshan Pig Conservation Farm. Results: The genetically closed conserved population consisted of five overlapping generations, and the total effective content of the population (Ne) was 15. The whole population was divided into five boar families and one non-boar family. Among them, the effective size of each generation subpopulation continuously decreased. However, the proportion of polymorphic markers (P_N) first decreased and then increased. The average genetic distance of these 139 Liangshan pigs was 0.2823±0.0259, and the average genetic distance of the 14 boars was 0.2723±0.0384. Thus, it can be deduced that the genetic distance changed from generation to generation. In the conserved population, 983 runs of homozygosity (ROH) were detected, and the majority of ROH (80%) were within 100 Mb. The inbreeding coefficient calculated based on ROH showed an average value of 0.026 for the whole population. In addition, the inbreeding coefficient of each generation subpopulation initially increased and then decreased. In the pedigree of the whole conserved population, the error rate of paternal information was more than 11.35% while the maternal information was more than 2.13%. Conclusion: This molecular study of the population genetic structure of Liangshan pig showed loss of genetic diversity during the closed cross-generation reproduction process. It is necessary to improve the mating plan or introduce new outside blood to ensure long-term preservation of Liangshan pig.

• Journal of Life Science
• /
• v.16 no.2 s.75
• /
• pp.213-218
• /
• 2006

The study of genetic diversity and population structure was carried out in the Codium fragile using allozyme analysis. Although this species has been regarded as a ecologically and economically important source, there is no report on population structure in Korea. Starch gel electrophoresis was used to investigate the allozyme variation and genetic structure of four Korean populations of this species. Of the 15 genetic loci surveyed, nine (60.0%) was polymorphic in at least one population. Genetic diversity was high at the species level ($H_{ES}$=0.144), and, that of the population level was relatively low ($H_{EP}$=0.128). Nearly 87% of the total genetic diversity in C. fragile was apportioned within populations. The predominant asexual reproduction, population fragmentation, low fecundity, geographic isolation and colonization process are proposed as possible factors contributing to low genetic diversity in this species. The indirect estimated of gene flow based on $G_{ST}$ was 1.69. The moderate level of gene flow in C. fragile populations is mainly caused by thallus developed from isolated utricles dispersal via sea current.

• Asian-Australasian Journal of Animal Sciences
• /
• v.33 no.11
• /
• pp.1732-1740
• /
• 2020

Objective: The objectives of this study were to investigate the genetic diversity, population structure and relatedness among the five chicken populations of Bangladesh using microsatellite markers. Methods: A total of 161 individuals representing 5 chicken populations (non-descript Deshi [ND], naked neck [NN], hilly [HI], Aseel [AS], and red jungle fowl [JF]) were included in this study to investigate genetic diversity measures, population structure, genetic distance and phylogenetic relationships. Genotyping was performed using 16 selected polymorphic microsatellite markers distributed across 10 chromosomes. Results: The average observed and expected heterozygosity, mean number of alleles and polymorphic information content were found to be 0.67±0.01, 0.70±0.01, 10.7 and 0.748, respectively in the studied populations. The estimated overall fixation index across the loci (F), heterozygote deficiency within (F_IS) and among (F_IT) chicken populations were 0.04±0.02, 0.05 and 0.16, respectively. Analysis of molecular variance analysis revealed 88.07% of the total genetic diversity was accounted for within population variation and the rest 11.93% was incurred with population differentiation (F_ST). The highest pairwise genetic distance (0.154) was found between ND and AS while the lowest distance was between JF and AS (0.084). Structure analysis depicted that the studied samples can be categorized into four distinct types or varieties (ΔK = 3.74) such as ND, NN, and HI where AS and JF clustered together as an admixed population. The Neighbor-Joining phylogenetic tree and discriminant analysis of principal component also showed close relatedness among three chicken varieties namely AS, HI, and JF. Conclusion: The results reflected that indigenous chicken of Bangladesh still possess rich genetic diversity but weak differentiation among the studied populations. This finding provides some important insight on genetic diversity measures that could support the designing and implementing of future breeding plans for indigenous chickens of Bangladesh.

• Journal of Preventive Medicine and Public Health
• /
• v.25 no.3 s.39
• /
• pp.303-311
• /
• 1992

It is very important to estimate the future medical care expenditure, because medical care expenditure escalation is a big problem not only in the health industry but also in the Korean economy today. This study was designed to project the medical care expenditure in view of population age change. The data of this study were the population projection data based on National Census Data(1990) of the National Statistical Office and the Statistical Reports of the Korea Medical Insurance Corporation. The future medical care expenditure was eatimated by the regression model and the optional simulation model. The significant results are as follows : 1. The future medical care expenditure will be 3,963 billion Won in the year 2000, 4,483 billion Won in 2010, and 4,826 billion Won in 2020, based on the 1990 market price considering only the population age change. 2. The proportion of the total medical care expenditure in the elderly over 65 will be 10.4% in 2000, 13.5% in 2010, and 16.9% in 2020. 3. The future medical care expenditure will be 4,306 billion Won in the year 2000, 5,101 billion Won in 2010, and 5,699 billion Won in 2020 based on the 1990 market price considering the age structure change and the change of the case-cost estimated by the regression model. 4. When we consider the age-structure change and inflation compared with the preceding year, the future medical care expenditurein 2020 will be 21 trillion Won based on a 5% inflation rate, 42 trillion Won based on a 7.5% inflation rate, and 84 trillion Won based on a 10% inflation rate. Consideration of the aged(65 years old and over) will be essential to understand the acute increase of medical care expenditure due to changes in age structure of the population. Therefore, alternative policies and programs for the caring of the aged should be further studied.

• Industry Promotion Research
• /
• v.6 no.1
• /
• pp.79-86
• /
• 2021

Due to the change in the demographic structure, the problem of low birth rate and aging population leads to a serious decrease in human resources, and the necessity of introducing foreign workers is increasing. This study believes that the introduction of foreign workforce is the most effective to expand the working-age population in the era of low birthrate and aging, when demographic changes begin in earnest, and to this end, it sought to devise measures to improve the legal system for migrant workers. As a result of this study, first, the legal system for migrant workers should be unified and improved. It is necessary to establish or unify management agencies so that the 「Immigration Control Act」 and the 「Labor Act」 can establish a cooperative relationship. Second, the 「Immigration Control Act」 should be revised to make it easier for migrant workers to find employment. It is necessary to positively review the employment permit system and acquisition of nationality. Third, there should be no equity or discrimination against migrant workers. Under the principle of mutual benefit, employers and migrant workers should not be equally discriminated against. Fourth, the social insurance system must be added to the legal system of migrant workers. Therefore, the legal system should be reorganized so that migrant workers are not discriminated against in various insurance systems including the four major social insurance systems. In conclusion, the problem of low birthrate and aging population has become a serious social problem due to changes in the demographic structure, and the decrease in the possible generation population has reached a level of concern. The importance of migrant workers' employment and work environment is increasing. Nevertheless, related legal and institutional problems still exist, and measures to improve the legal system for migrant workers are needed.