Stoop W M, Schennink A, Visker M H P W, Mullaart E, van Arendonk J A M, Bovenhuis H
Animal Breeding and Genomics Centre, Wageningen University, Wageningen, the Netherlands.
J Dairy Sci. 2009 Sep;92(9):4664-75. doi: 10.3168/jds.2008-1966.
A genome-wide scan was performed to identify quantitative trait loci (QTL) for short- and medium-chain fatty acids (expressed in wt/wt %). Milk samples were available from 1,905 cows from 398 commercial herds in the Netherlands, and milk-fat composition was measured by gas chromatography. DNA was available from 7 of the paternal half-sib families: 849 cows and their 7 sires. A genetic map was constructed comprising 1,341 SNP and 2,829 cM, with an average information content of 0.83. Multimarker interval mapping was used in an across-family regression on corrected phenotypes for the 7 half-sib families. Four QTL were found: on Bos taurus autosome (BTA) 6, a QTL was identified for C6:0 and C8:0; on BTA14, a QTL was identified for fat percentage, all odd-chain fatty acids, and C14:0, C16:0, C16:1, and their unsaturation indices; on BTA19, a QTL affected C14:0; and on BTA26, a QTL was identified for the monounsaturated fatty acids and their unsaturation indices. The QTL explained 3 to 19% of phenotypic variance. Furthermore, 49 traits with suggestive evidence for linkage were found on 21 chromosomes. Additional analyses revealed that the QTL on BTA14 was most likely caused by a mutation in DGAT1, whereas the QTL on BTA26 was most likely caused by a mutation in the SCD1 gene. Quantitative trait loci that affect specific fatty acids might increase the understanding of physiological processes regarding fat synthesis and the position of the causal genes.
进行了全基因组扫描，以鉴定短链和中链脂肪酸（以重量/重量百分比表示）的数量性状基因座（QTL）。从荷兰398个商业牛群的1905头奶牛中获取了牛奶样本，并通过气相色谱法测量了乳脂肪成分。有来自7个父系半同胞家系的DNA：849头奶牛及其7头公牛。构建了一个包含1341个单核苷酸多态性（SNP）和2829厘摩（cM）的遗传图谱，平均信息含量为0.83。对7个半同胞家系的校正表型进行跨家系回归，使用多标记区间作图法。发现了4个QTL：在牛1号常染色体（BTA）6上，鉴定出一个影响C6:0和C8:0的QTL；在BTA14上，鉴定出一个影响脂肪百分比、所有奇数链脂肪酸以及C14:0、C16:0、C16:1及其不饱和度指数的QTL；在BTA19上，一个QTL影响C14:0；在BTA26上，鉴定出一个影响单不饱和脂肪酸及其不饱和度指数的QTL。这些QTL解释了3%至19%的表型变异。此外，在21条染色体上发现了49个具有连锁暗示证据的性状。进一步分析表明，BTA14上的QTL最有可能是由二酰甘油酰基转移酶1（DGAT1）中的突变引起的，而BTA26上的QTL最有可能是由硬脂酰辅酶A去饱和酶1（SCD1）基因中的突变引起的。影响特定脂肪酸的数量性状基因座可能会增加对脂肪合成生理过程以及因果基因位置的理解。
