• Korean Journal of Poultry Science
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• v.48 no.4
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• pp.177-184
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• 2021

Sex identification in day-old chicks is essential in the poultry industry. Currently, the feather-sexing using a sex-linked inheritance is a chick sexing method used extensively in the poultry industry. For chicks produced by feather-sexing, all females are early-feathering (EF) chicks and all males are late-feathering (LF) chicks. Therefore, investigating the effects of EF and LF phenotypes on production traits of chickens is critical. The purpose of this study was to analyze and compare the production performance between EF and LF chickens in Korean native commercial chickens. The results showed that the survival rate of the EF chickens was significantly higher than that of the LF chickens, from hatching to 12 weeks of age (P<0.05), with the highest difference observed in females. However, no significant difference was observed in body weight between the EF and LF chickens at almost all ages. In addition, no significant difference was observed between in feed utility, such as average daily feed intake and feed conversion ratio, between the EF and LF groups. In conclusion, although the survival rate of early-feathering chickens was superior to that of late-feathering chickens, no significant difference was observed in growth performance and feed utility among Korean native chickens. The results suggest that production capacity is not influenced by feathering type in the establishment of a breeder structure and production system for feather-sexing Korean native chickens, which is valuable for the practical application of feather-sexing in the poultry industry.

• Korean Journal of Breeding Science
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• v.51 no.4
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• pp.318-325
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• 2019

Salt stress is a significant factor limiting growth and productivity in crops. However, little is known about the response and resistance mechanism to salt stress in maize. The objective of this research was to develop an enhanced salt-tolerant silage maize by mutagenesis with gamma radiation. To generate gamma radiation-induced salt-tolerant silage maize, we irradiated a KS140 inbred line with 100 Gy gamma rays. Salt tolerance was determined by evaluating plant growth, morphological changes, and gene expression under NaCl stress. We screened 10 salt-tolerant maize inbred lines from 2,248 M₂ mutant populations and selected a line showing better growth under salt stress conditions. The selected 140RS516 mutant exhibited improved seed germination and plant growth when compared with the wild-type under salt stress conditions. Enhanced salt tolerance of the 140RS516 mutant was attributed to higher stomatal conductance and proline content. Using whole-genome re-sequencing analysis, a total of 328 single nucleotide polymorphisms and insertions or deletions were identified in the 140RS516 mutant. We found that the expression of the genes involved in salt stress tolerance, ABP9, CIPK21, and CIPK31, was increased by salt stress in the 140RS516 mutant. Our results suggest that the 140RS516 mutant induced by gamma rays could be a good material for developing cultivars with salt tolerance in maize.

• Korean Journal of Head & Neck Oncology
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• v.9 no.1
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• pp.25-32
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• 1993

The nodular hyperplasia of the thyroid is a common thyriod disease. Nodular hyperplasia does rarely progress to thyroid cancer. The differentiation of a nodular hyperplasia from a neoplasm may be simple or difficult, both clinically and anatomically. The papillary carcinoma of the thyroid is the most common type of thyroid malignancies. There were few studies about cytogenetic observation in thyroid cancer. But only one case of banding observation in nodular hyperplasia have been reported. In order to compare the chromosomal changes in the thyroid cancer and the noncancerous thyroid disease, we performed cytogenetic analysis in two papillary carcinoma and two nodular hyperplasia after cell culture. The chromosomal pattern of the nodular hyperplasia found was very heterogenous but no clonal abnormaly in both cases was observed. Case I : A modal chromosomal number was in 42-46 range. Chromosome 8, 19, 21. 22 were commonly lost. 9 structural anomalities among 51 analysed cells were observed but they were not clonal. Case II: A modal chromosomal number was 43. Chromosome 17 and 19 were commonly lossed. Common cytogenetic characters of this two nodular hyperplasia are hypodiploidity and very heterogenous chromosomal pattern. The result about the papillary carcinoma are as follow. In one case some numerical and structural chromosomal changes were observed. But they were not clonal abnormality. In another case the chromosomal pattern found was very heterogenous with a clonal abnormality of del(11)(q23). The modal number was 46. The del(11)(q23) a chromosomal change in papillary carcinoma of the thyroid have previously been reported(Eva Olah et al. 1989). We suggest that 11q deletion may be important role to pathogenesis of papillary carcinoma of the thyroid. According to this results, we could not find out specific differences about chromosomal changes and any relationship between the papillary carcinoma and the nodular hyperplasia.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.6
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• pp.684-696
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• 1995

A mutant for chalky endosperm and genetic male sterility (GMS) was newly developed in rice. The two characters were found to be controlled by single recessive gene which has pleiotropic effect, indicating that chalky seeds should be GMS seeds in segregating populations. Chalky seeds showed the same shape and size as normal seeds. However, starch composition of central part of endosperm was looser and shape of starch granules was rounder compared with normal endosperm, resulting in significantly lower grain weight, absolute density and grain hardness in chalky grains than in normal ones. Amylose content and gel consistency of chalky grains were much lower and harder, respectively. Male sterile plants showed much shorter plant height, poorer panicle exsertion and lesser panicle number compared with normal plants. Microspore abortion stage in pollen developmental process was observed as before meiosis. Male sterility of the mutant was stable regadless of temperature and day length. A system breeding hybrid rice using this mutant was discussed, comp ring with other systems utilizing cytoplasmic-genic male sterility(CGMS) and environment sensitive GMS(EGMS). Separation of GMS seeds in mixed seed bulks by specific gravity (1.14∼1.16g / cm3) was successful about 85∼90%. But some mixed normal plants were seemed to be easily removed by the apparent difference in growth characters at seedling stage. The highest natural outcrossing rate of this GMS line was as 17.3 % in a plot treated with 2-row pollinator, I-row GMS, and GA3 + cutting of flag leaf + pollen-scattering by rope.

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.263-270
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• 2013

The vent sexing and the auto-sexing by using sex-linked traits are general sexing methods of day-old chicks. Currently, the feather sexing which is based on the differences in the feather characteristics at hatching is the representative sexing method of chicken, because the late-feathering is sex-linked trait. The feather sexing can be used if the breed has dominant feathering gene (K) in maternal and recessive gene ($k^+$) in paternal. Therefore it is necessary to identify the association of feathering genes and quantitative traits in chickens. In this study, we investigated the influence of the rate of feathering on productive traits in Korean Native Chicken. In results, there was no significant difference between early-feathering chickens and late-feathering chickens in reproductive performance such as fertility and hatchability. Livability, body weights, egg production, egg weight and egg quality also did not significantly differ between early- and late-feathering chickens. Age at first egg was the only trait of those tested in which significant difference was observed. The early-feathering chickens laid eggs 3 days earlier than late-feathering chicken. As a result, there is no influence of feathering phenotypes on productive performance in Korean Native Chickens. Consequentially, establishing the feather sexing strain is available using the Korean Native Chicken breed without considering of the effect of feathering genes on productive traits.

• The Korean Journal of Zoology
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• v.19 no.3
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• pp.101-112
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• 1976

1. It has been found in the karyotype of Apodemus agrarius coreae that No. 1 chromosome pair is subtelocentric and this is the new chromosome type in comparison with acro-telocentric No. 1 pair of the other subpecies. 2. It was reported in the Karyotype of Microtus fortis from USSR that the autosome consisted of 2 submetacentric, 10 metacentric and 38 acrocentric chromosomes, and that X is acrocentric and Y is small acrocentric one. In the present study, however, the autosome of M. fortis pelliceus in Korea is composed of three groups; 4 subtelocentric, 10 meta-submetacenric, and 36 acrocentric one. And X is the largest metacentric chromosome of the complement. Y is smaller acrocentric one. Thus, it has been found that the karyotype of M. fortis in Korea differs from that of the same species in USSR. In the karyotype of this red vole, two pairs of heteromorohic chromosome with respect to the size of their secondary constrictions have been shown in the acrocentric group. 3. The diploid number of Cricetulus triton nestor was found to be 28, and its chromosome size ranges from 7.5 $\\mu$ to 1.5 $\\mu$. Autosomes contains 11 large acrocentric pairs and two pairs of very small metacentric ones. This feature is simillar to that of Tscherskia triton found USSR.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.387-395
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• 2018

This study was conducted to identify DNA markers related to resistance to herbicide containing mesotrione in Tongil type rice. Two Tongil type elite lines; Milyang154 and Suweon382, showed resistance to mesotrione, whereas the others were susceptible at 20 days after mesotrione application, and severe growth inhibition was observed in the remaining 13 lines. As a result of analysis of mesotrione resistance using 190 $F_2$ populations derived from a cross of Hanareum2 (susceptible) and Milyang154 (resistant), the mesotrione resistance locus was shown to be a single dominant gene with a 3:1 segregation ratio ($X^2=1.19$, P=0.31). To identify a DNA marker closely linked to the mesotrione resistance gene, bulked segregant analysis (BSA) was adopted. The DNA marker RM3501 was identified on chromosome 2 with a recombinant value of 0.53 to the mesotrione resistance gene. Mst1(t) was located between SSR (simple sequence repeat) markers RM3501 and RM324 with a physical map distance of 10.2 Mb-11.4 Mb on chromosome 2. The band pattern of agarose gel electrophoresis of the SSR marker RM3501 showed the same segregation pattern with respect to mesotrione treatment in 20 Tongil type varieties and a $BC_2F_2$ segregation population derived from a cross between Unkwang (resistant) and Hanareum2 (susceptible). Thus, the RM3501 DNA marker could be used in breeding programs for Marker Assisted Selection in mesotrione resistant rice breeding.

• Korean Journal of Poultry Science
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• v.24 no.4
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• pp.169-177
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• 1997

Four experiments were conducted to investigate the association of yolk cholesterol level with egg trails, serum cholesterol level, body weight (BW) and breed differences and other variations. Athens Canadian Randombred (ACRB), a commercial layer breed (CL) and two commercial broiler breeds (BR1 and BR2) were used for this studies. Egg weight of CL was heavier by 8.7g per egg than that of ACRB, but the yolk percentage and yolk cholesterol were lower by 7.8％ per egg and 5.5mg per g yolk than those of ACRB, respectively. Yolk cholesterol content had no significant relation with the average egg weight or yolk weight in ACRB, but was significantly related with yolk fat level. However, yolk cholesterol level in CL showed inverse relationship with other egg traits compared to that of ACRB. In the CL female group, the association of yolk cholesterol level with BW was significant(P$\leq$0.05) at 25 weeks of age, but was not significant different at 26 wks of age. The relationship of yolk cholesterol with serum was not significantly different at 25 weeks of age, whereas it showed significant negative(-) correlation coefficient(P$\leq$0.01) at 26 wks of age. The association of yolk cholesterol level with egg age in CL population was not high comared to that of other treatments. The serum cholesterol content of CL was not significantly different with BR1 and BR2 populations at 25 weeks of age, but was significantly(P$\leq$0.05) higher than that of BR1 or BR2 at 26 weeks old.

• Journal of Preventive Medicine and Public Health
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• v.18 no.1
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• pp.99-112
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• 1985

It was measured to check the state of health education by the survey of the items related to the health with the first grade of students in middle school who mastered elementary courses. Totally 50 questions, which were selected from Standard and Dong-A reference books, were given to teachers and have got answered by the students who were totally 959(491 from urban areas and 468 from rural areas). It's done just after they entered middle school for a month, from April 10 to may 10, 1984. There were totally 782 items of health in all subjects of all grades. In contents, the most cases were about mental and emotional health(17.7%), exercise and rest (15.1%), environmental health, health life, personal health care, nutrition and foods, social health and organization, physiology and anatomy, statistics of public health population problem, disease and care, food sanitation, school health, parasitic and communicable disease control, eugenics and heredity(0.4%), etc were followed. In subjects, Korean language had 44.7% of mental and emotional health in 114 cases, arithmetics 46.4% of statistics of public health in 26, sociology, 23.1% of environmental health in 118, natural science, 60.1% of physiology and anatomy in 30, ethics, 40.3% of mental and emotional health in 176, music, 21.8% of mental and emotional health and accidents in 23, art, 42.9% of exercise and rest in 28, physical education, 38.6% of exercise and rest in 201, practical course, 36.2% of nutrition and foods in 61, and there was nothing but only one case in Korean history. Subjects in total cases of health informing items are below: Physical education 25.8, ethics 22.5%, sociology 15.1%, Korean language 14.6%, practical course 7.8%, natural science 3.8%, art 3.6%, arithmetics 3.3%, music 2.9%, Korean history 0.6%. Grades in total cases of health informing items are belows: the sixth grade 29.1%, the fourth grade 21.2%, the fifth grade 18.9%, the third grade 11.6%, the first grade 11.5%, the second grade 7.7%. The sections related to health matters were average 35.4%. According to the grades, the fourth and the sixth grade were 38.2% each other, the highest, and the second grade was 29.3%, the lowest. All scetions in physical education included them. The acceptability to the knowledge for health was belows: 56.3% in urban students and 53.9% in rural students. There was some difference in acceptability between two parties (p<0.005).

• The korean journal of orthodontics
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• v.34 no.3 s.104
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• pp.261-267
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• 2004

Nonsyndromic cleft lip and/or palate (NSCLP) is one of the most common congenital deformities and its prevalence in Far East Asia, such as within Korean and Japanese populations, is relatively high. However, in the eastern part of Europe, clefts are relatively rare situations. These ethnic differences infer a genetic background of the disease. The objective of this study was to compare the frequency of single nucleotide polymorphism (SNP) in $TGF-{\beta}3$ between Korean and Romanian cleft families. Korean cleft families samples were collected from twenty-six families (n=78) and Romanian cleft families samples were collected from eighteen families (n=41). For sequencing, the blood or saliva of the subjects was sampled. A single nucleotide polymorphism was observed in the intron 5 of $TGF-{\beta}3$ (Al8141G). The frequency of each allele was significantly different between the Korean and Romanian samples. The Ah allele was present in 18 out of 78 Korean samples (23.1%) and in 27 out of 41 Romanian samples (65.9%). The AG was present in 27 (34.6%) out of 78 Koreans and in 13 (31.7%) out of 41 Romanians. The GG was found in 33 (42.3%) Koreans and in 1 (2.4%) Romanian. The difference between the groups was significant (p<0.001). In conclusion, the frequency of observed SNP was significantly different between the two countries. SNP in $TGF-{\beta}3$ in the Korean population seemed to have a higher possibility of occurrence for nonsyndromic cleft palate than the Romanian population.