Refined positioning of a quantitative trait locus affecting somatic cell score on chromosome 18 in the German Holstein using linkage disequilibrium
Refined positioning of a quantitative trait locus affecting somatic cell score on chromosome 18 in the German Holstein using linkage disequilibrium
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DOI：
10.3168/jds.2008-1742
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发表时间：
2009-08-01
影响因子：
3.5
通讯作者：
Reinsch, N.
中科院分区：
文献类型：
--
作者：
Baes, C.;Brand, B.;Reinsch, N.
为了更准确地定位一个先前报道的影响牛18号染色体体细胞评分的数量性状位点，进行了连锁和连锁不平衡分析（LALD）。在这项研究中使用了一个孙女设计，包括6个德国荷斯坦大公猪家庭，1,054个后代测试基因型的儿子。20个微卫星标记，5个单核苷酸多态性，和红细胞抗原标记的平均标记间距为1.95 cM沿着50.80 cM的染色体片段进行了分析。估计方差分量，并在每个标记间隔的中点计算限制性最大似然检验统计量。单QTL连锁分析的检验统计量在几个假定的QTL位点上超过了全基因组显著性阈值。使用LALD，我们成功地分配了一个全基因组显着QTL的标记ILSTS 002和BMS 833之间的置信区间为10.8 cM。在这个标记区间的QTL估计是负责之间的5.89和13.86%的体细胞评分的遗传变异。与单QTL连锁分析模型相反，2-QTL模型的LALD分析证实了一个QTL的位置，但没有给出第二个QTL的存在或位置的确凿证据。最终，QTL的位置被大大缩小了与以前的结果相比，一个精确的置信区间小于11 cM。
Combined linkage and linkage disequilibrium analysis (LALD) was conducted to more accurately map a previously reported quantitative trait locus (QTL) affecting somatic cell score on bovine chromosome 18. A granddaughter design consisting of 6 German Holstein grandsire families with 1,054 progeny-tested genotyped sons was used in this study. Twenty microsatellite markers, 5 single nucleotide polymorphisms, and an erythrocyte antigen marker with an average marker spacing of 1.95 cM were analyzed along a chromosomal segment of 50.80 cM. Variance components were estimated and restricted maximum likelihood test statistics were calculated at the midpoint of each marker interval. The test statistics calculated in single-QTL linkage analysis exceeded the genome-wide significance threshold at several putative QTL positions. Using LALD, we were successful in assigning a genome-wide significant QTL to a confidence interval of 10.8 cM between the markers ILSTS002 and BMS833. The QTL in this marker interval was estimated to be responsible for between 5.89 and 13.86% of the genetic variation in somatic cell score. In contrast to the single-QTL linkage analysis model, LALD analyses with a 2-QTL model confirmed the position of one QTL, but gave no conclusive evidence for the existence or position of a second QTL. Ultimately, the QTL position was narrowed down considerably compared with previous results with a refined confidence interval of less than 11 cM.