Fine-mapping of quantitative trait loci by identity by descent in outbred populations: Application to milk production in dairy cattle
Fine-mapping of quantitative trait loci by identity by descent in outbred populations: Application to milk production in dairy cattle
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DOI：
10.1073/pnas.96.16.9252
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发表时间：
1999-08-03
影响因子：
11.1
通讯作者：
Georges, M
中科院分区：
文献类型：
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作者：
Riquet, J;Coppieters, W;Georges, M
我们将一个影响产奶量的QTL定位在牛14号染色体上。为了精确定位该QTL，我们增加了9个微卫星和3个单核苷酸多态性位点，以提高遗传图谱的密度。QTL的精细定位通过两层方法完成。在第一阶段，我们通过标记辅助分离分析，在一个包含1,158个个体的荷斯坦-弗里斯兰牛家系中鉴定了7个QTL的杂合“Qq”父系。在第二阶段，我们对新开发的高密度标记图谱的7个选定的公牛进行基因分型，并搜索一个共享的单倍型，该单倍型位于一个假设的、具有大取代效应的血统相同的QTL等位基因的侧翼。增加乳脂百分比的七条染色体确实显示携带一个共同的染色体片段，其估计大小为5cM，预测包含所研究的QTL。相同的单倍型也显示与一般群体中增加的脂肪百分比相关，这为QTL在相应区间内的位置提供了额外的支持。
We previously mapped a quantitative trait locus (QTL) affecting milk production to bovine chromosome 14, To refine the map position of this QTL, we have increased the density of the genetic map of BTA14q11-16 by addition of nine microsatellites and three single nucleotide polymorphisms. Fine-mapping of the QTL was accomplished by a two-tiered approach. In the first phase, we identified seven sires heterozygous "Qq" for the QTL by marker-assisted segregation analysis in a Holstein-Friesian pedigree comprising 1,158 individuals. In a second phase, we genotyped the seven selected sires for the newly developed high-density marker map and searched for a shared haplotype flanking an hypothetical, identical-by-descent QTL allele with large substitution effect. The seven chromosomes increasing milk fat percentage were indeed shown to carry a common chromosome segment with an estimated size of 5 cM predicted to contain the studied QTL, The same haplotype was shown to be associated with increased fat percentage in the general population as well, providing additional support in favor of the location of the QTL within the corresponding interval.