Li C, Basarab J, Snelling W M, Benkel B, Kneeland J, Murdoch B, Hansen C, Moore S S
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada.
J Anim Sci. 2004 Apr;82(4):967-72. doi: 10.2527/2004.824967x.
Backfat thickness is one of the major quantitative traits that affects carcass quality in beef cattle. In this study, we identified and fine-mapped QTL for backfat EBV on bovine chromosomes 2, 5, 6, 19, 21, and 23 using an identical-by-descent haplotype-sharing analysis in a commercial line of Bos taurus. Eleven haplotypes were found to have significant associations with backfat EBV at the comparison-wise P-value threshold, and one at the chromosome-wise P-value threshold on bovine chromosomes 5, 6, 19, 21, and 23. On average, the 12 significant haplotypes had an effect of 0.62 SD on backfat EBV, ranging from 0.38 SD to 1.33 SD. The 12 significant haplotypes spanned nine chromosomal regions, one on chromosome 5 (65.4 to 70.0 cM), three on 6 (8.2 to 11.8 cM, 63.6 to 68.1 cM, and 81.5 to 83.0 cM), three on 19 (4.8 to 15.9 cM, 39.4 to 46.5 cM, and 65.7 to 99.5 cM), one on 21 (46.1 to 53.1 cM), and one on 23 (45.1 to 50.9 cM). Among the nine chromosomal regions, six were new QTL regions and three showed remarkable agreement with QTL regions that were previously reported. Eight of the nine QTL regions were localized to less than or close to 10 cM in genetic distance. The results provide a useful reference for further positional candidate gene research and marker-assisted selection for backfat.
背膘厚度是影响肉牛胴体品质的主要数量性状之一。在本研究中，我们利用家系内等位基因相同的单倍型共享分析，在一个商业品种的肉牛中，对牛2号、5号、6号、19号、21号和23号染色体上的背膘估计育种值（EBV）进行了QTL定位和精细定位。在比较水平的P值阈值下，发现11个单倍型与背膘EBV有显著关联，在牛5号、6号、19号、21号和23号染色体上，有1个单倍型在染色体水平的P值阈值下与背膘EBV有显著关联。平均而言，这12个显著单倍型对背膘EBV的影响为0.62个标准差，范围从0.38个标准差到1.33个标准差。这12个显著单倍型跨越9个染色体区域，1个在5号染色体上（65.4至70.0 cM），3个在6号染色体上（8.2至11.8 cM、63.6至68.1 cM和81.5至83.0 cM），3个在19号染色体上（4.8至15.9 cM、39.4至46.5 cM和65.7至99.5 cM），1个在21号染色体上（46.1至53.1 cM），1个在23号染色体上（45.1至50.9 cM）。在这9个染色体区域中，6个是新的QTL区域，3个与先前报道的QTL区域有显著一致性。9个QTL区域中有8个定位在遗传距离小于或接近10 cM的区域。这些结果为进一步的位置候选基因研究和背膘的标记辅助选择提供了有用的参考。
