• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.303-313
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• 2020

Rice grain shape is one of the key components of grain yield and market value. An understanding of the genetic basis of the variation in grain shape could be used to improve grain shape. In this study, we developed a total of 265 F₂ individuals derived from a cross between japonica cultivars (Josaeng-jado and Langi) and used this population for quantitative trait locus (QLT) analysis. Correlation analysis was performed to identify relationships between grain traits (GL: grain length, GW: grain width, L/W: ratio of length to width, TGW: 1,000 grain weight). The grain shape was positively correlated with GL and TGW, and negatively correlated with GW. In QTL analysis associated with grain shape, one QTL for GL, qGL5, detected on chromosome 5, explained 20.3% of the phenotypic variation (PV), while two QTLs, qGW5 (PV=36.1) and qGW7 (PV=26.1), for GW were identified on chromosomes 5 and 7, respectively. Evaluation of the effects of each of the QTLs on the grain shape in the population showed a significant difference in the grain size in positive lines compared with the lines without the QTLs. According to the QTL combination of the allelic-types, the grain shape of the tested lines varied from semi-round type to long spindle-shaped type. The results of this study extend our knowledge about the genetic pool governing the diversity of grain shape in japonica cultivars and could be used to improve the grain shape of this species through marker-assisted selective breeding in Korea.

• The Korean Journal of Nuclear Medicine
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• v.35 no.2
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• pp.83-88
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• 2001

Purpose: The purpose of this study was to ascertain whether radiation adaptive response could be induced by high dose I-131 therapy in patients with differentiated thyroid cancer. Materials and Methods: Lymphocytes from 21 patients (7 males, 14 females, mean age $55{\pm}12$ years) were collected before and after administration of 5,550 MBq (150 mCi) I-131. They were exposed to a challenge dose of 1 Gy gamma rays using a Cs-137 cell irradiator. The number of ring-form (R) and dicentric (D) chromosomes was counted under the light microscope, and used to calculate the frequency of chromosomal aberration. Ydr, which was defined as the sum of R and D divided by the total number of counted lymphocytes. Results: Ydr in patients before I-131 therapy ($0.09{\pm}0.01$) was not different from that of controls ($0.08{\pm}0.01$). Ydr was significantly increased to $0.13{\pm}0.02$ (p<0.0001) after I-131 therapy. Increase of Ydr after the challenge irradiation of 1 Gy was significantly lower in patients after I-131 therapy than before I-131 therapy ($0.17{\pm}0.03\;vs\;0.21{\pm}0.02$, p<0.0001). Cycloheximide (CHM), an inhibitor of protein synthesis, abolished this effect. Ydr after CHM ($0.20{\pm}0.01$) was significantly higher than Ydr after I-131 therapy ($0.17{\pm}0.03$, p<0.0001), but was not different from Ydr before I-131 therapy ($0.21{\pm}0.02$).Conclusion: High dose I-131 therapy induces an adaptive response in peripheral lymphocytes of patients with well-differentiated thyroid cancer, which is associated with protein synthesis.

• Journal of Animal Science and Technology
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• v.54 no.5
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• pp.323-329
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• 2012

Genome-wide association study was performed on data from 266 Hanwoo steers derived from 66 sires using bovine 10K mapping chip in Hanwoo (Korean cattle). SNPs were excluded from the analysis if they failed in over 5% of the genotypes, had median GC scores below 0.6, had GC scores under 0.6 in less than 90% of the samples, deviated in heterozygosity more than 3 standard deviations from the other SNPs and were out of Hardy-Weinberg equilibrium for a cut-off p-value of $1^{-15}$. Unmapped and SNPs on sex chromosomes were also excluded. A total of 4,522 SNPs were included in the analysis. To test an association between SNP and QTL, a single marker regression analysis was implemented in this study. SNP was assumed to be in LD with QTL in close proximity and the effect evaluated was additive effect (QTL allele substitution effect). The number of significant SNP at a threshold of P<0.001 was 3, 5, 5 and 4 loci for live weight at 6, 12, 18 and 24 months, respectively. For live weight at different ages, significant SNP were spread out across chromosome but some of significant SNP (rs29012453 and rs29012456 on BTA24) had shown highly significant effects. As for the distribution of size of SNP effects, few loci for live weight at different age had moderate effects (6~11%) but most of significant loci had small effects (2 to 5% of additive genetic variance) against total additive genetic variance. In conclusion, live weight at different age might be affected by few loci with moderate effect and many loci with small effects across genome in Hanwoo.