Ashwell M S, Van Tassell C P, Sonstegard T S
Agricultural Research Service, USDA, Beltsville, MD 20705, USA.
J Dairy Sci. 2001 Nov;84(11):2535-42. doi: 10.3168/jds.S0022-0302(01)74705-4.
Quantitative trait loci affecting economically important traits were studied for eight large US Holstein grandsire families by using the granddaughter design. A total of 155 microsatellite markers located throughout the bovine genome were selected for the scan. The data analyzed include genotypes for 50 markers not previously reported. Results analyses of 105 marker genotypes reported previously were updated. Effects of marker alleles were analyzed for 38 traits including traits for milk production, somatic cell score, productive life, conformation, calving ease, and 16 canonical traits derived from conformation and production traits. Permutation tests were used to calculate empirical traitwise error rates. A traitwise critical value of P = 0.1 was used to determine significance. Ten putative quantitative trait loci associated with seven of the new markers were identified within specific families. One marker on chromosome 14 was associated with differences in fat yield, fat percentage, and a canonical production trait in two families. Markers on chromosomes 18 and 22 were associated with differences in rump angle in the same family. Markers were associated with differences in udder depth and fore udder attachment on chromosomes 16 and 20, respectively. One marker on chromosome 27 was associated with a difference in the dairy capacity composite index, and another marker on chromosome 13 was associated with a difference in a canonical conformation trait. These additional markers complete our genome scan to identify quantitative trait loci affecting economically important traits in a selected commercial Holstein population. The quantitative trait loci identified in this genome scan may be useful for marker-assisted selection to increase the rate of genetic improvement on traits such as disease resistance and conformation traits associated with fitness while accelerating genetic improvement for production.
利用孙女设计法，对美国8个大型荷斯坦公牛家族中影响经济重要性状的数量性状位点进行了研究。共选择了遍布牛基因组的155个微卫星标记进行扫描。分析的数据包括50个先前未报道的标记的基因型。对先前报道的105个标记基因型的结果分析进行了更新。分析了标记等位基因对38个性状的影响，这些性状包括产奶量、体细胞评分、生产寿命、体型、产犊难易度，以及从体型和生产性状衍生出的16个典型性状。采用置换检验来计算经验性的性状特异性错误率。使用P = 0.1的性状特异性临界值来确定显著性。在特定家族中鉴定出了与7个新标记相关的10个假定数量性状位点。14号染色体上的一个标记与两个家族的脂肪产量、脂肪百分比和一个典型生产性状的差异相关。18号和22号染色体上的标记与同一家族的臀角差异相关。16号和20号染色体上的标记分别与乳房深度和前乳房附着的差异相关。27号染色体上的一个标记与奶牛综合能力指数的差异相关，13号染色体上的另一个标记与一个典型体型性状的差异相关。这些额外的标记完成了我们的基因组扫描，以识别影响选定商业荷斯坦种群中经济重要性状的数量性状位点。在这次基因组扫描中鉴定出的数量性状位点可能有助于标记辅助选择，以提高抗病性和与适应性相关的体型性状等性状的遗传改良率，同时加速生产性状的遗传改良。
