• Asian-Australasian Journal of Animal Sciences
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• 제23권10호
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• pp.1261-1267
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• 2010

Milk production traits are important economic traits for dairy cattle. The aim of the present study was to refine the position of previously detected quantitative trait loci (QTL) on bovine chromosome 6 affecting milk production traits in Chinese Holstein dairy cattle. A daughter design with 918 daughters from 8 elite sire families and 14 markers spanning the previously identified QTL region were used in the analysis. We employed a combined linkage and linkage disequilibrium analysis (LDLA) approach with two options for calculating the IBD probabilities, one was based on haplotypes of all 14 markers (named Method 1) and the other based on haplotypes with sliding windows of 5 markers (named Method 2). For milk fat yield, the two methods revealed a highly significant QTL located within a 6.5 cM interval (Method 1) and a 4.0 cM interval (Method 2), respectively. For milk protein yield, a highly significant QTL was detected within a 3.0 cM interval (Method 1) or a 2.5 cM interval (Method 2). These results confirmed the findings of our previous study and other studies, and greatly narrowed down the QTL positions.

• Asian-Australasian Journal of Animal Sciences
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• 제28권7호
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• pp.926-935
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• 2015

The efficiency of genome-wide association analysis (GWAS) depends on power of detection for quantitative trait loci (QTL) and precision for QTL mapping. In this study, three different strategies for GWAS were applied to detect QTL for carcass quality traits in the Korean cattle, Hanwoo; a linkage disequilibrium single locus regression method (LDRM), a combined linkage and linkage disequilibrium analysis (LDLA) and a $BayesC{\pi}$ approach. The phenotypes of 486 steers were collected for weaning weight (WWT), yearling weight (YWT), carcass weight (CWT), backfat thickness (BFT), longissimus dorsi muscle area, and marbling score (Marb). Also the genotype data for the steers and their sires were scored with the Illumina bovine 50K single nucleotide polymorphism (SNP) chips. For the two former GWAS methods, threshold values were set at false discovery rate <0.01 on a chromosome-wide level, while a cut-off threshold value was set in the latter model, such that the top five windows, each of which comprised 10 adjacent SNPs, were chosen with significant variation for the phenotype. Four major additive QTL from these three methods had high concordance found in 64.1 to 64.9Mb for Bos taurus autosome (BTA) 7 for WWT, 24.3 to 25.4Mb for BTA14 for CWT, 0.5 to 1.5Mb for BTA6 for BFT and 26.3 to 33.4Mb for BTA29 for BFT. Several candidate genes (i.e. glutamate receptor, ionotropic, ampa 1 [GRIA1], family with sequence similarity 110, member B [FAM110B], and thymocyte selection-associated high mobility group box [TOX]) may be identified close to these QTL. Our result suggests that the use of different linkage disequilibrium mapping approaches can provide more reliable chromosome regions to further pinpoint DNA makers or causative genes in these regions.

• 생명과학회지
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• 제24권11호
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• pp.1168-1173
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• 2014

HGD (homogentisate1,2-dioxygenase)유전자는 소의 1번 염색체에 존재하며, tyrosine과 phenylalanine의 이화 작용을 돕는 효소 중 하나로 알려져 있다. 또한 소에서 도체중과 등심단면적에 영향을 주는 유전자로 보고된 바 있다. 본 연구는 한우 집단을 대상으로 HGD유전자내 변이지역을 탐색하고, 경제형질과의 연관성을 분석하기 위하여 실시하였다. 총 14개의 Exon지역을 바탕으로 변이지역을 탐색한 결과, 10개의 SNPs를 확인하였고, 이 중 genotype의 Frequency (MAF>0.1)를 고려하여 6개의 SNPs (G34256T, G34257C, T34284C, T42333G, T42348C, T42468C)를 발굴하여 경제형질과의 연관성을 분석하였다. 그 결과 G34256T에서 근내지방도와 유의적인 연관성이 확인되었고, G34257C에서 등심단면적과 근내지방도에서 유의적인 연관성이 확인되었다. 따라서 본 연구 결과에서 확인된 HGD 유전자의 SNP유전자형은 한우선발 및 개량을 위한 분자육종의 기초 자료로 이용할 수 있을 것으로 사료된다.