• 제목/요약/키워드: genome-wide linkage analysis

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Genetics of Alzheimer's Disease

  • Kim, Jong Hun
    • 대한치매학회지
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    • 제17권4호
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    • pp.131-136
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    • 2018
  • Alzheimer's disease (AD) related genes have been elucidated by advanced genetic techniques. Familial autosomal dominant AD genes founded by linkage analyses are APP, PSEN1, PSEN2, ABCA7, and SORL1. Genome-wide association studies have found risk genes such as ABCA7, BIN1, CASS4, CD33, CD2AP, CELF1, CLU, CR1, DSG2, EPHA1, FERMT2, HLA-DRB5-HLA-DRB1, INPP5D, MEF2C, MS4A6A/MS4A4E, NME8, PICALM, PTK2B, SLC24A4, SORL1, and ZCWPW1. ABCA7, SORL1, TREM2, and APOE are proved to have high odds ratio (>2) in risk of AD using next generation sequencing studies. Thanks to the promising genetic techniques such as CRISPR-CAS9 and single-cell RNA sequencing opened a new era in genetics. CRISPR-CAS9 can directly link genetic knowledge to future treatment. Single-cell RNA sequencing are providing useful information on cell biology and pathogenesis of diverse diseases.

Genome-wide analysis of Hanwoo and Chikso populations using the BovineSNP50 genotyping array

  • Song, Jun?Seok;Seong, Ha?Seung;Choi, Bong?Hwan;Lee, Chang?Woo;Hwang, Nam?Hyun;Lim, Dajeong;Lee, Joon?Hee;Kim, Jin Soo;Kim, Jeong?Dae;Park, Yeon?Soo;Choi, Jung?Woo;Kim, Jong?Bok
    • Genes and Genomics
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    • 제40권12호
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    • pp.1373-1382
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    • 2018
  • Hanwoo and Chikso are classified as Korean native cattle breeds that are currently registered with the Food and Agriculture Organization. However, there is still a lack of genomic studies to compare Hanwoo to Chikso populations. The objective of this study was to perform genome-wide analysis of Hanwoo and Chikso populations, investigating the genetic relationships between these two populations. We genotyped a total of 319 cattle including 214 Hanwoo and 105 Chikso sampled from Gangwon Province Livestock Technology Research Institute, using the Illumina Bovine SNP50K Beadchip. After performing quality control on the initially generated datasets, we assessed linkage disequilibrium patterns for all the possible SNP pairs within 1 Mb apart. Overall, average $r^2$ values in Hanwoo (0.048) were lower than Chikso (0.074) population. The genetic relationship between the populations was further assured by the principal component analysis, exhibiting clear clusters in each of the Hanwoo and Chikso populations, respectively. Overall heterozygosity for Hanwoo (0.359) was slightly higher than Chikso (0.345) and inbreeding coefficient was also a bit higher in Hanwoo (-0.015) than Chikso (-0.035). The average $F_{ST}$ value was 0.036 between Hanwoo and Chikso, indicating little genetic differentiation between those two breeds. Furthermore, we found potential selection signatures including LRP1B and NTRK2 genes that might be implicated with meat and reproductive traits in cattle. In this study, the results showed that both Hanwoo and Chikso populations were not under severe level of inbreeding. Although the principal component analysis exhibited clear clusters in each of the populations, we did not see any clear evidence that those two populations are highly differentiated each other.

Comparison of prediction accuracy for genomic estimated breeding value using the reference pig population of single-breed and admixed-breed

  • Lee, Soo Hyun;Seo, Dongwon;Lee, Doo Ho;Kang, Ji Min;Kim, Yeong Kuk;Lee, Kyung Tai;Kim, Tae Hun;Choi, Bong Hwan;Lee, Seung Hwan
    • Journal of Animal Science and Technology
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    • 제62권4호
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    • pp.438-448
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    • 2020
  • This study was performed to increase the accuracy of genomic estimated breeding value (GEBV) predictions for domestic pigs using single-breed and admixed reference populations (single-breed of Berkshire pigs [BS] with cross breed of Korean native pigs and Landrace pigs [CB]). The principal component analysis (PCA), linkage disequilibrium (LD), and genome-wide association study (GWAS) were performed to analyze the population structure prior to genomic prediction. Reference and test population data sets were randomly sampled 10 times each and precision accuracy was analyzed according to the size of the reference population (100, 200, 300, or 400 animals). For the BS population, prediction accuracy was higher for all economically important traits with larger reference population size. Prediction accuracy was ranged from -0.05 to 0.003, for all traits except carcass weight (CWT), when CB was used as the reference population and BS as the test. The accuracy of CB for backfat thickness (BF) and shear force (SF) using admixed population as reference increased with reference population size, while the results for CWT and muscle pH at 24 hours after slaughter (pH) were equivocal with respect to the relationship between accuracy and reference population size, although overall accuracy was similar to that using the BS as the reference.

Whole genome sequencing of Luxi Black Head sheep for screening selection signatures associated with important traits

  • Liu, Zhaohua;Tan, Xiuwen;Wang, Jianying;Jin, Qing;Meng, Xianfeng;Cai, Zhongfeng;Cui, Xukui;Wang, Ke
    • Animal Bioscience
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    • 제35권9호
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    • pp.1340-1350
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    • 2022
  • Objective: Luxi Black Head sheep (LBH) is the first crossbreed specialized for meat production and was developed by crossbreeding Black Head Dorper sheep (DP) and Small Tailed Han sheep (STH) in the farming areas of northern China. Research on the genomic variations and selection signatures of LBH caused by continuous artificial selection is of great significance for identifying the genetic mechanisms of important traits of sheep and for the continuous breeding of LBH. Methods: We explored the genetic relationships of LBH, DP, and several Mongolian sheep breeds by constructing phylogenetic tree, principal component analysis and linkage disequilibrium analysis. In addition, we analysed 29 whole genomes of sheep. The genome-wide selection signatures have been scanned with four methods: heterozygosity (HP), fixation index (FST), cross-population extended haplotype homozygosity (XP-EHH) and the nucleotide diversity (𝜃π) ratio. Results: The genetic relationships analysis showed that LBH appeared to be an independent cluster closer to DP. The candidate signatures of positive selection in sheep genome revealed candidate genes for developmental process (HoxA gene cluster, BCL2L11, TSHR), immunity (CXCL6, CXCL1, SKAP2, PTK6, MST1R), growth (PDGFD, FGF18, SRF, SOCS2), and reproduction (BCAS3, TRIM24, ASTL, FNDC3A). Moreover, two signalling pathways closely related to reproduction, the thyroid hormone signalling pathway and the oxytocin signalling pathway, were detected. Conclusion: The selective sweep analysis of LBH genome revealed candidate genes and signalling pathways associated with developmental process, immunity, growth, and reproduction. Our findings provide a valuable resource for sheep breeding and insight into the mechanisms of artificial selection.

Genotyping-by-sequencing 기법을 이용한 사시나무(Populus davidiana) 유전연관지도 작성 및 양적형질 유전자좌 탐색 (Construction of Genetic Linkage Map and Identification of Quantitative Trait Loci in Populus davidiana using Genotyping-by-sequencing)

  • 김수비;김양길;이다영;이혜진;강규석
    • 한국산림과학회지
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    • 제112권1호
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    • pp.40-56
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    • 2023
  • 사시나무속 수종은 생장이 빠르고 우수한 탄소흡수 능력을 보여주며, 환경정화 효과가 큰 수종으로 이상기후 및 환경오염 문제에 대응하는 기후적응성 품종개발 및 육종집단 조성에 적합하다. 따라서 유전연관지도 작성 및 양적형질 유전자좌 탐색을 통하여 포플러 육종을 신속하게 진행할 수 있을 것이다. 본 연구에서는 차세대 염기서열 분석기술 방법인 genotyping-by-sequencing 기법을 이용해 인공교배 차대에 대한 고밀도 유전연관 지도를 작성하였다. 또한 사시나무의 수고와 근원경 생장 그리고 해충피해에 대한 회복력 형질을 조사하여 유전연관지도에 위치한 양적형질 유전자좌를 탐색하였다. 서울대학교 학술림에 조성된 사시나무 4년생 육종집단(오대19 × 봉현4 인공교배 차대집단)에서 수고 및 근원경 생장을 조사하였으며, 식엽성 해충인 꼬마버들재주나방 유충의 피해를 받은 후 이에 대해 회복 능력을 조사하였다. 잎 시료의 DNA 추출 후 5개 microsatellite 마커를 이용하여 유전자형을 확인하였으며 친자로 확인된 개체만을 연구재료로 사용하였다. 친자 확인이 완료된 시료의 DNA는 제한효소를 이용해 절단하였으며, 이렇게 얻은 DNA 조각들은 GBS 라이브러리로 제작하여 염기서열을 분석하였다. 분석된 결과는 Populus trichocarpa를 참조유전체로 하여 정렬하였다. 정렬된 SNP 마커는 총 58,040개였으며, 그 가운데 17,755개의 SNP 마커를 유전연관지도 작성에 사용하였다. 유전연관지도는 19개의 연관군으로 나누어졌으며, 전체 길이는 2,129.54 cM으로 나타났다. 조사된 세 가지 형질에 대한 양적형질 유전자좌 분석을 실시한 결과, 수고와 근원경 생장과 연관된 양적형질 유전자좌는 찾을 수 없었으나 전장유전체연관연구(GWAS)를 통하여 4번 연관군(염색체)에 해충피해 회복력과 관련이 있을 것으로 추정되는 유전자를 확인하였다.

Identification of the quantitative trait loci (QTL) for seed protein and oil content in soybean.

  • Jeong, Namhee;Park, Soo-Kwon;Ok, Hyun-Choong;Kim, Dool-Yi;Kim, Jae-Hyun;Choi, Man-Soo
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2017년도 9th Asian Crop Science Association conference
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    • pp.148-148
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    • 2017
  • Soybean is an important economical resource of protein and oil for human and animals. The genetic basis of seed protein and oil content has been separately characterized in soybean. However, the genetic relationship between seed protein and oil content remains to be elucidated. In this study, we used a combined analysis of phenotypic correlation and linkage mapping to dissect the relationship between seed protein and oil content. A $F_{10:11}$ RIL population containing 222 lines, derived from the cross between two Korean soybean cultivars Seadanbaek as female and Neulchan as male parent, were used in this experiment. Soybean seed analyzed were harvested in three different experimental environments. A genetic linkage map was constructed with 180K SoyaSNP Chip and QTLs of both traits were analyzed using the software QTL IciMapping. QTL analyses for seed protein and oil content were conducted by composite interval mapping across a genome wide genetic map. This study detected four major QTL for oil content located in chromosome 10, 13, 15 and 16 that explained 13.2-19.8% of the phenotypic variation. In addition, 3 major QTL for protein content were detected in chromosome 10, 11 and 16 that explained 40.8~53.2% of the phenotypic variation. A major QTLs was found to be associated with both seed protein and oil content. A major QTL were mapped to soybean chromosomes 16, which were designated qHPO16. These loci have not been previously reported. Our results reveal a signi cant genetic relationship between seed protein and oil fi content traits. The markers linked closely to these major QTLs may be used for selection of soybean varieties with improved seed protein and oil content.

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SNP Discovery from Transcriptome of Cashmere Goat Skin

  • Wang, Lele;Zhang, Yanjun;Zhao, Meng;Wang, Ruijun;Su, Rui;Li, Jinquan
    • Asian-Australasian Journal of Animal Sciences
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    • 제28권9호
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    • pp.1235-1243
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    • 2015
  • The goat Capra hircus is one of several economically important livestock in China. Advances in molecular genetics have led to the identification of several single nucleotide variation markers associated with genes affecting economic traits. Validation of single nucleotide variations in a whole-transcriptome sequencing is critical for understanding the information of molecular genetics. In this paper, we aim to develop a large amount of convinced single nucleotide polymorphisms (SNPs) for Cashmere goat through transcriptome sequencing. In this study, the transcriptomes of Cashmere goat skin at four stages were measured using RNA-sequencing and 90% to 92% unique-mapped-reads were obtained from total-mapped-reads. A total of 56,231 putative SNPs distributed among 10,057 genes were identified. The average minor allele frequency of total SNPs was 18%. GO and KEGG pathway analysis were conducted to analyze the genes containing SNPs. Our follow up biological validation revealed that 64% of SNPs were true SNPs. Our results show that RNA-sequencing is a fast and efficient method for identification of a large number of SNPs. This work provides significant genetic resources for further research on Cashmere goats, especially for the high density linkage map construction and genome-wide association studies.

Sample Size and Statistical Power Calculation in Genetic Association Studies

  • Hong, Eun-Pyo;Park, Ji-Wan
    • Genomics & Informatics
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    • 제10권2호
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    • pp.117-122
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    • 2012
  • A sample size with sufficient statistical power is critical to the success of genetic association studies to detect causal genes of human complex diseases. Genome-wide association studies require much larger sample sizes to achieve an adequate statistical power. We estimated the statistical power with increasing numbers of markers analyzed and compared the sample sizes that were required in case-control studies and case-parent studies. We computed the effective sample size and statistical power using Genetic Power Calculator. An analysis using a larger number of markers requires a larger sample size. Testing a single-nucleotide polymorphism (SNP) marker requires 248 cases, while testing 500,000 SNPs and 1 million markers requires 1,206 cases and 1,255 cases, respectively, under the assumption of an odds ratio of 2, 5% disease prevalence, 5% minor allele frequency, complete linkage disequilibrium (LD), 1:1 case/control ratio, and a 5% error rate in an allelic test. Under a dominant model, a smaller sample size is required to achieve 80% power than other genetic models. We found that a much lower sample size was required with a strong effect size, common SNP, and increased LD. In addition, studying a common disease in a case-control study of a 1:4 case-control ratio is one way to achieve higher statistical power. We also found that case-parent studies require more samples than case-control studies. Although we have not covered all plausible cases in study design, the estimates of sample size and statistical power computed under various assumptions in this study may be useful to determine the sample size in designing a population-based genetic association study.

Reverse Random Amplified Microsatellite Polymorphism Reveals Enhanced Polymorphisms in the 3' End of Simple Sequence Repeats in the Pepper Genome

  • Min, Woong-Ki;Han, Jung-Heon;Kang, Won-Hee;Lee, Heung-Ryul;Kim, Byung-Dong
    • Molecules and Cells
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    • 제26권3호
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    • pp.250-257
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    • 2008
  • Microsatellites or simple sequence repeats (SSR) are widely distributed in eukaryotic genomes and are informative genetic markers. Despite many advantages of SSR markers such as a high degree of allelic polymorphisms, co-dominant inheritance, multi-allelism, and genome-wide coverage in various plant species, they also have shortcomings such as low polymorphic rates between genetically close lines, especially in Capsicum annuum. We developed an alternative technique to SSR by normalizing and alternating anchored primers in random amplified microsatellite polymorphisms (RAMP). This technique, designated reverse random amplified microsatellite polymorphism (rRAMP), allows the detection of nucleotide variation in the 3' region flanking an SSR using normalized anchored and random primer combinations. The reproducibility and frequency of polymorphic loci in rRAMP was vigorously enhanced by translocation of the 5' anchor of repeat sequences to the 3' end position and selective use of moderate arbitrary primers. In our study, the PCR banding pattern of rRAMP was highly dependent on the frequency of repeat motifs and primer combinations with random primers. Linkage analysis showed that rRAMP markers were well scattered on an intra-specific pepper map. Based on these results, we suggest that this technique is useful for studying genetic diversity, molecular fingerprinting, and rapidly constructing molecular maps for diverse plant species.

Positional mapping for foxglove aphid resistance with 180k SNP array in soybean [Glycine max (L.) Merr.]

  • Park, Sumin;Kim, Kyung Hye;Go, Hong Min;Lee, Ju Seok;Jung, Jin Kyo;Bilyeu, Kristin D.;Lee, Jeong-Dong;Kan, Sungtaeg
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2017년도 9th Asian Crop Science Association conference
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    • pp.145-145
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    • 2017
  • Foxglove aphid, Aulacorthum solani (Kaltenbach), is a Hemipteran insect that infected a wide variety of plants worldwide and caused serious yield losses in crops. The objective of this study was to identify the putative genes to foxglove aphid resistance in wild soybean, PI 366121 (Glycine soja Sieb. and Zucc.). One hundred and forty-one F4:8 recombinant inbred lines developed from a cross between susceptible variety, Williams 82 and foxglove aphid resistance wild soybean, PI 366121 were used. The two type of resistance response, antibiosis and antixenosis resistance were evaluated through choice and no-choice test, graded by the degree of total plant damage and primary infestation leaf damage; a genome-wide molecular linkage map was constructed with 29,898 single-nucleotide polymorphism markers utilizing a Axiom(R) 180K soyaSNP array. Using inclusive composite interval mapping analysis for foxglove aphid resistance, one major candidate QTL on chromosome 7 was identified. The major QTL on chromosome 7 showed both antixenosis and antibiosis resistance responses. The newly identified major QTL was consistent with previously reported QTL, Raso2, which showed around 5 times narrow down interval range with 8 candidate genes. Furthermore, total 1,115 soybean varieties including Glycine soja and Glycine max were exposed to germplasm screening, and 31 varieties, which showed significant antibiosis type foxglove aphid resistance were identified. This result could be useful in breeding for new foxglove aphid resistant soybean cultivars and developing novel insecticides.

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