• Asian-Australasian Journal of Animal Sciences
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• 제12권7호
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• pp.1129-1134
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• 1999

The rapid development of the sheep genetic linkage map over the last five years has given us the ability to follow the inheritance of chromosomal regions. Initially this powerful resource was used to find markers linked to monogenic traits but there is now increasing interest in using the genetic linkage map to define the complex of genes that control multigenic production traits. Of particular interest are those production traits that are difficult to measure and select for using classical quantitative genetic approaches. These include resistance to disease where a disease challenge (necessary for selection) poses too much risk to valuable stud animals and meat and carcass qualities which can be measured only after the animal has been slaughtered. The goal for the new millennium will be to fully characterise the genetic basis of multigenic production traits. The genetic linkage map is a vital tool required to achieve this.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1995년도 제9회 식물생명공학 심포지움 식물육종과 분자생물학의 만남 The 9th Plant Biotechnology Symposium -Breeding and Molecular Biology-
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• pp.57-86
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• 1995

Molecular mapping of plant genomes has progressed rapidly since Bostein et al.(1980) introduced the idea of constructing linkage maps of human genome based on restriction fragment length polymorphism (RFLP) markers. In recent years, the development of protein and DNA markers has stimulated interest for the new approaches to plant improvement. While classical maps based on morphological mutant markers have provided important insights into the plant genetics and cytology, the molecular maps based on molecular markers have a number of inherent advatages over classical genetic maps for the applications in genetic studies and/or breeding schemes. Isozymes and DNA markers are numerous, discrete, non-deleterious, codominant, and almost entirely free of environmental and epistatic interactions. For these reasons, they are widely used in constructing detailed linkage maps in a number of plant species. Plant breeders improve crops by selecting plants with desirable phenotypes. However a plant's phenotyes is often under genetic control, positioning at different "quantitative trait loci" (QTLs) together with environmental effects. Molecular maps provide a possible way to determine the effect of the individual gene that combines to produce a quantitative trait because the segregation of a large number of markers can be followed in a single genetic cross. Using market-assisted selection, plants that contain several favorable genes for the trait and do not contain unfavourable segments can be obtained during early breeding processes. Providing molecular maps are available, valuable data relevant to the taxonomic relationships and chromosome evolution can be accumulated by comparative mapping and also the structural relationships between linkage map and physical map can be identified by cDNA sequencing. After constructing high density maps, it will be possible to clone genes, whose products are unknown, such as semidwarf and disease resistance genes. However, much attention has to be paid to level-up the basic knowledge of genetics, physiology, biochemistry, plant pathology, entomology, microbiology, and so on. It must also be kept in mind that scientists in various fields will have to make another take off by intensive cooperation together for early integration and utilization of these newly emerging high-techs in practical breeding. breeding.

• Asian-Australasian Journal of Animal Sciences
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• 제32권3호
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• pp.341-349
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• 2019

Objective: Internal organs indirectly affect economic performance and well-being of animals. Study of internal organs during later layer period will allow full utilization of layer hens. Hence, we conducted a genome-wide association study (GWAS) to identify potential quantitative trait loci or genes that potentially contribute to internal organ weight. Methods: A total of 1,512 chickens originating from White Leghorn and Dongxiang Blue-Shelled chickens were genotyped using high-density Affymetrix 600 K single nucleotide polymorphism (SNP) array. We conducted a GWAS, linkage disequilibrium analysis, and heritability estimated based on SNP information by using GEMMA, Haploview and GCTA software. Results: Our results displayed that internal organ weights show moderate to high (0.283 to 0.640) heritability. Variance partitioned across chromosomes and chromosome lengths had a linear relationship for liver weight and gizzard weight ($R^2=0.493$, 0.753). A total of 23 highly significant SNPs that associated with all internal organ weights were mainly located on Gallus gallus autosome (GGA) 1 and GGA4. Six SNPs on GGA2 affected heart weight. After the final analysis, five top SNPs were in or near genes 5-Hydroxytryptamine receptor 2A, general transcription factor IIF polypeptide 2, WD repeat and FYVE domain containing 2, non-SMC condensin I complex subunit G, and sonic hedgehog, which were considered as candidate genes having a pervasive role in internal organ weights. Conclusion: Our findings provide an understanding of the underlying genetic architecture of internal organs and are beneficial in the selection of chickens.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.282-282
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• 2022

Arsenic (As) is a toxic heavy metal that affects the major rice-growing regions of the world and can cause cancer in humans. Rice paddy fields in South Asia are mostly dependent on arsenic-contaminated water sources due to which rice takes up the arsenic from the soil through roots and accumulates it in plant different parts. Here, we present a quantitative trait locus (QTL) mapping study to find out candidate genes conferring As toxicity tolerance in rice (Oryza sativa L.) at the seedling stage. Three weeks old, 120 double haploid CNDH lines derived from a cross between the Indica variety Cheongcheong and the Japonica variety Nagdong and their parental lines were used by treating with 25 μM As. After 2 weeks ofAs stress, 5 traits such as; shoot length (SL), root length (RL), shoot fresh weight (SFW), root fresh weight (RFW), and chlorophyll contents (CHC) were measured. A linkage map of 12 rice chromosomes was constructed from genotypic data DH lines using 778 SSR markers. The linkage map covered a total genetic distance of 2121.7 cM of the rice genome with an average interval of 10.6 cM between markers. A total of seventeen QTLs (LOD>2) were mapped on chromosomes 1, 2, 3, 6, 7, 8, 9, 11, and 12 using composite interval mapping with trait-increasing alleles coming from both parents. Five QTLs for SL, Two QTLs for RL, Five QTLs for SHL, Three QTLs for RFW, and Two QTLs for CHC were detected. The QTLs related to CHC were selected for forther study.

• 생명과학회지
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• 제16권6호
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• pp.949-954
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• 2006

콩은 전 세계 시장의 48%를 차지하는 중요한 유료작물이다. 콩 종자를 구성하는 양적인 부분과 질적인 부분의 개선은 콩 육종 목표의 중요한 부분이다. 단백질함량과 종실의 크기는 두부와 콩나물의 질을 평가하는 중요한 특성이다. 따라서 본 연구는 콩에서 종실의 크기와 단백질 및 oil 함량을 조절하는 양적형질유전자좌(QTLs)를 확인하기 위하여 실시하였다. 시험재료로는 큰올콩과 신팔달콩을 교배한 후 $F_2$유래 $F_10$세대의 RIL을 이용하였으며, 이를 바탕으로 종실의 무게와 oil 및 단백질 함량과 관련된 QTLs를 탐색하였다. 종실의 무게와 단백질 및 oil 함량의 협의의 유전력은 각각 0.8과 0.78 및 0.71을 나타내었다. 종실의 무게와 관련된 QTLs는 연관군 F, I와 K의 세 개의 독립적인 QTLs를 확인하였다. 단백질함량과 관련된 QTLs는 연관군 D1b, E, H, I와 L의 다섯 개의 독립적인 QTLs를 확인하였다. 그리고 oil 함량과 관련된 QTLs는 연관군 D1b, E, G, I, J와 N의 여섯 개의 독립적인 QTLs를 확인하였다. oil 및 단백질 함량과 관련된 QTLs는 연관군 D1b, E와 I에서 공통적으로 나타났다. 따라서 이들 주요 QTL은 콩 품종 육성과정에서 품질의 개선하기 위한 선발 마커로서 활용가치가 높은 것으로 판단된다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권12호
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• pp.1675-1683
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• 2005

In the process of crossbreeding, the linkage disequilibria between the quantitative trait loci (QTL) and their linked markers were reduced gradually with increasing generations. To study the potential of QTL mapping using the crossbred population, we presented a mixed effect model that treated the mean allelic value of the different founder populations as the fixed effect and the allelic deviation from the population mean as random effect. It was assumed that there were fifty QTLs having effect on the trait variation, the population mean and variance were divided to each QTL in founder generation in our model. Only the additive effect was considered in this model for simulation. Six schemes (S1-S6) of crossbreeding were studied. The selection index was used to evaluate the synthetic breeding value of two traits of the individual in the scheme of S2, S4 and S6, and the individuals with high selection index were chosen as the parents of the next generation. Random selection was used in the scheme of S1, S3 and S5. In this study, we premised a QTL explained 40% of the genetic variance was located in a region of 20 cM by the linkage analysis previously. The log likelihood ratio (log LR) was calculated to determine the presence of a QTL at the particular chromosomal position in each of the generations from the fourth to twentieth. The profiles of log LR and the number of the highest log LR located in the region of 5, 10 and 20 cM were compared between different generations and schemes. The profiles and the correct number reduced gradually with the generations increasing in the schemes of S2, S4 and S6, but both of them increased in the schemes of S1, S3 and S5. From the results, we concluded that the crossbreeding population undergoing random selection was suitable for improving the resolution of QTL mapping. Even experiencing index selection, there was still enough variation existing within the crossbred population before the fourteenth generation that could be used to refine the location of QTL in the chromosome region.

• Journal of Plant Biotechnology
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• 제50권
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• pp.142-154
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• 2023

식물의 탈리(abscission)는 기관 혹은 조직이 분리되는 현상으로, 필요 없어진 기관을 떨어트리거나 종자와 과실을 널리 퍼트리기 위해 자연이 선택해온 전략이다. 하지만 농업적 관점에서 이러한 종자나 과실의 탈리는 작물의 생산성과 상품의 품질을 떨어트리는 주요 요인이 될 수 있다. 때문에 전통 농업의 작물화 과정을 통해 탈리가 저해된 돌연변이들이 선택되어 교배되면서 자연적으로 익은 과일이나 종자를 떨어트리지 않는 현대의 벼, 토마토, 유채, 콩과 같은 주요 작물 품종을 얻을 수 있었다. 한 세기 가량 진행된 quantitative trait loci (QTLs) 연구 및 애기장대에서의 유전학적･분자생물학적 연구를 통해 탈리 활성에 관여하는 다양한 세포생물학적 메커니즘과 신호전달 경로 및 전사조절인자가 규명되었다. 뿐만 아니라, 식물 생장에 관여하는 다양한 호르몬 신호전달 역시 탈리 활성을 조절하는 데에 중요함이 밝혀졌으며, 이들 호르몬과 신호전달에 작용하는 여러 케미칼 처리제가 개발되어 작물의 수확량을 증대시키는데 사용되어왔다. 본 리뷰에선 최근까지 밝혀진 탈리 활성에 관여하는 신호전달과 주요 조절인자에 대해 소개하고, smart farm 시대의 미래농업에 적용되어야할 작물의 탈리 조절 메커니즘 연구가 무엇일지, 또 이를 위해 모델시스템에서 앞으로 더 연구되어야 할 것이 무엇인지에 대해 논의하고자 한다.

• Asian-Australasian Journal of Animal Sciences
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• 제30권8호
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• pp.1066-1073
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• 2017

Objective: Growth-related traits are important economic traits in the swine industry. However, the genetic mechanism of growth-related traits is little known. The aim of this study was to screen the candidate genes and molecular markers associated with body dimension and body weight traits in pigs. Methods: A genome-wide association study (GWAS) on body dimension and body weight traits was performed in a White $Duroc{\times}Erhualian$ $F_2$ intercross by the illumina PorcineSNP60K Beadchip. A mixed linear model was used to assess the association between single nucleotide polymorphisms (SNPs) and the phenotypes. Results: In total, 611 and 79 SNPs were identified significantly associated with body dimension traits and body weight respectively. All SNPs but 62 were located into 23 genomic regions (quantitative trait loci, QTLs) on 14 autosomal and X chromosomes in Sus scrofa Build 10.2 assembly. Out of the 23 QTLs with the suggestive significance level ($5{\times}10^{-4}$), three QTLs exceeded the genome-wide significance threshold ($1.15{\times}10^{-6}$). Except the one on Sus scrofa chromosome (SSC) 7 which was reported previously all the QTLs are novel. In addition, we identified 5 promising candidate genes, including cell division cycle 7 for abdominal circumference, pleiomorphic adenoma gene 1 and neuropeptides B/W receptor 1 for both body weight and cannon bone circumference on SSC4, phosphoenolpyruvate carboxykinase 1, and bone morphogenetic protein 7 for hip circumference on SSC17. Conclusion: The results have not only demonstrated a number of potential genes/loci associated with the growth-related traits in pigs, but also laid a foundation for studying the genes' role and further identifying causative variants underlying these loci.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.33-33
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• 2022

Rice (Oryza sativa L.) is a widely studied domesticated model plant. Seed awning is an unfavorable trait during rice harvesting and processing. Hence, awn was one of the target characters selected during domestication. However, the genetic mechanisms underlying awn development in rice are not well understood. In this study, we analyzed the genes for awn development using a mapping population derived from a cross between the Korean indica cultivar 'Milyang23' and NIL4/9 (derived from a cross between 'Hwaseong' and O. minuta). Two quantitative trait loci (QTLs), qAwn4 and qAwn9 were mapped on chromosome 4 and 9, respectively, increased awn length in an additive manner. Through comparative sequencing analyses parental lines, LABA1 was determined as the causal gene underlying qAwn4. qAwn9 was mapped to a 199-kb physical region between markers RM24663 and RM24679. Within this interval, 27 annotated genes were identified, and five genes, including a basic leucine zipper transcription factor 76 (OsbZIP76), were considered candidate genes for qAwn9 based on their functional annotations and sequence variations. Haplotype analysis using the candidate genes revealed tropical japonica specific sequence variants in the qAwn9 region, which partly explains the non-detection of qAwn9 in previous studies that used progenies from interspecific crosses. This provides further evidence that OsbZIP76 is possibly a causal gene for qAwn9. The O. minuta qAwn9 allele was identified as a major QTL associated with awn development in rice, providing an important molecular target for basic genetic research and domestication studies. Our results lay the foundation for further cloning of the awn gene underlying qAwn9.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.24-24
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• 2022

This present study was to identify a novel candidate gene that contribute to the elevated α-linolenic acid (ALA, ω-3) concentration in PE2166 from mutagenesis of Pungsannamul. Major loci qALA5_1 and qALA5_2 were detected on chromosome 5 of soybean through quantitative trait loci mapping analyses of recombinant inbred lines. With next generation sequencing of parental lines and Pungsannamul, and recombinant analyses, a potential gene, Glyma. 05g221500 (HD) controlling elevated ALA concentration was identified. HD is a homeodomain-like transcriptional regulator that may regulate the expression level of microsomal ω-3 fatty acid desaturase (FAD3) genes responsible for the conversion of linoleic acid into ALA in the fatty acid biosynthetic pathway. In addition, we hypothesized that combination of mutant alleles, HD and either of microsomal delta-12 fatty acid desaturase 2-1 (FAD2-1\ could reduce the ω-6/ω-3 ratio. In populations where HD, and FAD2-1A and FAD2-1B genes were segregated, combination of a hd allele from PE2166 and either of the variant FAD2-1 alleles were sufficient to reduce the ω-6/ω-3 ratio in seeds.