• Asian-Australasian Journal of Animal Sciences
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• v.21 no.3
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• pp.314-319
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• 2008

Duck (Anas platyrhynchos) is one of the most important domestic avian species in the world. In the present research, fifteen polymorphic microsatellite markers were used to evaluate the diversity and population structure of 26 Chinese indigenous duck breeds across the country. The Chinese breeds showed high variation with the observed heterozygosity (Ho) ranging from 0.401 (Jinding) to 0.615 (Enshi), and the expected heterozygosity (He) ranging from 0.498 (Jinding) to 0.707 (Jingjiang). In all of the breeds, the values of Ho were significantly lower than those of He, suggesting high selection pressure on these local breeds. AMOVA and Bayesian clustering analysis showed that some breeds had mixed together. The FST value for all breeds was 0.155, indicating medium differentiation of the Chinese indigenous breeds. The FST value also indicated the short domestication history of most of Chinese indigenous ducks and the admixture of these breeds after domestication. Understanding the genetic relationship and structure of these breeds will provide valuable information for further conservation and utilization of the genetic resources in ducks.

• Genomics & Informatics
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• v.16 no.1
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• pp.14-20
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• 2018

Despite the importance of mutation rate, some difficulties exist in estimating it. Next-generation sequencing (NGS) data yields large numbers of single-nucleotide polymorphisms, which can make it feasible to estimate substitution rates. The genetic substitution rates of Hanwoo and Holstein cattle were estimated using NGS data. Our main findings was to calculate the gene's substitution rates. Through estimation of genetic substitution rates, we found: diving region of altered substitution density exists. This region may indicate a boundary between protected and unprotected genes. The protected region is mainly associated with the gene ontology terms of regulatory genes. The genes that distinguish Hanwoo from Holstein in terms of substitution rate predominantly have gene ontology terms related to blood and circulatory system. This might imply that Hanwoo and Holstein evolved with dissimilar mutation rates and processes after domestication. The difference in meat quality between Hanwoo and Holstein could originate from differential evolution of the genes related to these blood and circulatory system ontology terms.

• Journal of Life Science
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• v.12 no.1
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• pp.27-32
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• 2002

Enzyme electrophoresis was used to estimate genetic diversity and population structure of maize, Zea mays L. (Graminales) in Korea. In nine populations, fourteen of the 24 loci (58.3 %) showed detectable polymorphism. Genetic diversity (0.205) was higher than average values for species with similar life history traits. Although our data are relatively small and the landraces not direct ancestors of cultivar, apparently the domestication process has eroded the levels of genetic variation of maize. The recent cultivars were found to have fewer alleles per locus (1.42 vs. 1.56), fewer alleles per polymorphic locus (2.27 vs. 2.33), lower percent polymorphic locus (33.3% vs. 41.7%), and lower diversity (0.159 vs. 0.185) than landraces. These genetic diversity parameters indicated that the cultivar populations were genetically depauperate relative to landlaces. The GST value of nine populations was 0.239. Nearly 76% of the total genetic diversity in Zea mays was apportioned within populations. The indirect estimate of gene new based on mean GST was moderate (Nm=0.80).

• Korean Journal of Poultry Science
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• v.23 no.3
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• pp.153-160
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• 1996

Though pheasants (Korean ring-necked pheasant) have been raised for several decades, their behavior and wild nature are far from domestication. The pheasant is a seasonal breeding species and lays a limited number of eggs in a breeding season. The growth rate and feed efficiency of pheasants are very low as compaired with those of chicken for meat purpose. In addition, the breeder's access to one's herd for care is not easy. From these reasons, pheasants seem to be unsuitable for meat production in a large flock at present. However, pheasant raising is expected to increase slowly in accordance with rising demand for special poultry meat. Therefore, it is necessary to improve techniques about raising, feeding and rnanagement, so that the consumer price of pheasant meat can be lowered down reasonably.

• Molecules and Cells
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• v.28 no.5
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• pp.423-430
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• 2009

In order to elucidate the precise phylogenetic relationships of Korean wild boar (Sus scrofa coreanus), a partial mtDNA D-loop region (1,274 bp, NC_000845 nucleotide positions 16576-1236) was sequenced among 56 Korean wild boars. In total, 25 haplotypes were identified and classified into four distinct subgroups (K1 to K4) based on Bayesian phylogenetic analysis using Markov chain Monte Carlo methods. An extended analysis, adding 139 wild boars sampled worldwide, confirmed that Korean wild boars clearly belong to the Asian wild boar cluster. Unexpectedly, the Myanmarese/Thai wild boar population was detected on the same branch as Korean wild boar subgroups K3 and K4. A parsimonious median-joining network analysis including all Asian wild boar haplotypes again revealed four maternal lineages of Korean wild boars, which corresponded to the four Korean wild boar subgroups identified previously. In an additional analysis, we supplemented the Asian wild boar network with 34 Korean and Chinese domestic pig haplotypes. We found only one haplotype, C31, that was shared by Chinese wild, Chinese domestic and Korean domestic pigs. In contrast to our expectation that Korean wild boars contributed to the gene pool of Korean native pigs, these data clearly suggest that Korean native pigs would be introduced from China after domestication from Chinese wild boars.

• Nuclear Engineering and Technology
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• v.41 no.5
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• pp.617-648
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• 2009

Under the government supported long-term nuclear R&D program, the severe accident research program at KAERI is directed to investigate unresolved severe accident issues such as core debris coolability, steam explosions, and hydrogen combustion both experimentally and numerically. Extensive studies have been performed to evaluate the in-vessel retention of core debris through external reactor vessel cooling concept for APR1400 as a severe accident management strategy. Additionally, an improvement of the insulator design outside the vessel was investigated. To address steam explosions, a series of experiments using a prototypic material was performed in the TROI facility. Major parameters such as material composition and void fraction as well as the relevant physics affecting the energetics of steam explosions were investigated. For hydrogen control in Korean nuclear power plants, evaluation of the hydrogen concentration and the possibility of deflagration-to-detonation transition occurrence in the containment using three-dimensional analysis code, GASFLOW, were performed. Finally, the integrated severe accident analysis code, MIDAS, has been developed for domestication based on MELCOR. The data transfer scheme using pointers was restructured with the modules and the derived-type direct variables using FORTRAN90. New models were implemented to extend the capability of MIDAS.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.5
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• pp.603-607
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• 2001

This paper is based on the 36 wild Japanese quails which migrated to and settled in the Weishan Lake area. The gene frequency of 10 loci encoding the enzymes in viscera and muscle was detected. After collecting the same data about 20 quail colonies in China and other countries, it clusters the 21 quail populations by fuzzy cluster analysis. The study indicates that the wild Japanese quail in the Weishan Lake area is closer to domestic quail for phylogenetic system than wild Japanese quails in Japanese Islands. The paper supports the thesis that the quail domestication area should be further studied.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.447-456
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• 2020

Peanut is an allotetraploid derived from a single recent polyploidization. Polyploidization has been reported to have caused significant loss in genetic diversity during the domestication of cultivated peanuts. Single nucleotide polymorphism (SNP)-based markers such as cleaved amplified polymorphic sequences (CAPS) derived from next-generation sequencing (NGS) have been developed and widely applied for breeding and genetic research in peanuts. This study aimed to identify the genetic diversity and population structure using 30 CAPS markers and 96 peanut accessions from five different origins. High genetic dissimilarities were detected between the accessions from Korea and those from the other three South American origins generally regarded as the origin of peanuts, while the accessions from Brazil and Argentina presented the lowest genetic dissimilarity. Based on the results of the present study, accessions from Korea have unique genetic variation compared to those from other countries, while accessions from the other four origins are closely related. Our study identified the genetic differentiation in 96 peanut accessions from five different origins, and this study also showed the successful application of SNP information derived from re-sequencing based on NGS technology.

• International Journal of Industrial Entomology and Biomaterials
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• v.19 no.1
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• pp.155-164
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• 2009

The most important factors in environment that influence the physiology of insects are temperature and humidity. Insects display a remarkable range of adaptations to changing environments and maintain their internal temperature (thermoregulation) and water content within tolerable limits, despite wide fluctuations in their surroundings. Adaptation is a complex and dynamic state that widely differs in species. Surviving under changing environment in insects depends on dispersal, habitat selection, habitat modification, relationship with ice and water, resistance to cold, diapause and developmental rate, sensitivity to environmental signals and syntheses of variety of cryoprotectant molecules. The mulberry silkworm (Bombyx mori) is very delicate and sensitive to environmental fluctuations and unable to survive naturally because of their domestication since ancient times. Thus, the adaptability to environmental conditions in the silkworm is quite different from those of wild insects. Temperature, humidity, air circulation, gases and photoperiod etc. shows a significant interaction in their effect on the physiology of silkworm depending upon the combination of factors and developmental stage affecting growth, development, productivity and quality of silk. An attempt has been made in this article to briefly discuss adaptation in insects with special emphasis on the role of environmental factors and their fluctuations and its significance in the physiology of mulberry silkworm, B. mori.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.10
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• pp.1478-1484
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• 2007

To determine the origin and genetic diversity of Red Chittagong (RC) cattle in Bangladesh, we analyzed mitochondrial DNA displacement loop (D-loop) sequences of 48 samples along with 22 previously published sequences from Bos indicus and Bos taurus breeds. Twenty five haplotypes were identified in RC cattle that were defined by 44 polymorphic sites and nucleotide diversity was $0.0055{\pm}0.0026$. The estimated sequence divergence times between RC and other zebu cattle breeds studied ranged between 22,700-26,900 years before present (YBP) which, it is suggested, predate domestication of RC cattle. Furthermore, it is assumed that introgressions have occurred in this breed mainly from Indian zebu breeds in the recent millennia. The phylogenetic studies showed RC cattle clustered with Bos indicus lineage with two distinct haplogroups representing high genetic variability of this breed. These findings can be used for designing proper breeding and conservation strategies for RC cattle in Bangladesh.