Bouwman Aniek C, Visker Marleen H P W, van Arendonk Johana M, Bovenhuis Henk
Animal Breeding and Genomics Centre, Wageningen University, PO Box 338, 6700 AH Wageningen, the Netherlands.
Animal Breeding and Genomics Centre, Wageningen University, PO Box 338, 6700 AH Wageningen, the Netherlands.
J Dairy Sci. 2014 Feb;97(2):1139-49. doi: 10.3168/jds.2013-7197. Epub 2013 Dec 6.
A major quantitative trait locus (QTL) for milk fat content and fatty acids in both milk and adipose tissue has been detected on Bos taurus autosome 19 (BTA19) in several cattle breeds. The objective of this study was to refine the location of the QTL on BTA19 for bovine milk fat composition using a denser set of markers. Opportunities for fine mapping were provided by imputation from 50,000 genotyped single nucleotide polymorphisms (SNP) toward a high-density SNP panel with up to 777,000 SNP. The QTL region was narrowed down to a linkage disequilibrium block formed by 22 SNP covering 85,007 bp, from 51,303,322 to 51,388,329 bp on BTA19. This linkage disequilibrium block contained 2 genes: coiled-coil domain containing 57 (CCDC57) and fatty acid synthase (FASN). The gene CCDC57 is minimally characterized and has not been associated with bovine milk fat previously, but is expressed in the mammary gland. The gene FASN has been associated with bovine milk fat and fat in adipose tissue before. This gene is a likely candidate for the QTL on BTA19 because of its involvement in de novo fat synthesis. Future studies using sequence data of both CCDC57 and FASN, and eventually functional studies, will have to be pursued to assign the causal variant(s).
在多个牛品种中，已在牛19号常染色体（BTA19）上检测到一个影响牛奶脂肪含量以及牛奶和脂肪组织中脂肪酸的主要数量性状位点（QTL）。本研究的目的是使用更密集的标记集来精确定位BTA19上影响牛乳脂肪成分的QTL。通过将50,000个基因分型的单核苷酸多态性（SNP）推算至包含多达777,000个SNP的高密度SNP面板，提供了精细定位的机会。QTL区域被缩小至一个由22个SNP形成的连锁不平衡区域，覆盖85,007 bp，位于BTA19上51,303,322至51,388,329 bp处。这个连锁不平衡区域包含2个基因：卷曲螺旋结构域蛋白57（CCDC57）和脂肪酸合酶（FASN）。CCDC57基因的特征描述极少，之前未发现其与牛乳脂肪有关，但在乳腺中表达。FASN基因之前已被发现与牛乳脂肪和脂肪组织中的脂肪有关。由于该基因参与从头脂肪合成，它很可能是BTA19上QTL的候选基因。未来需要对CCDC57和FASN的序列数据进行研究，并最终开展功能研究，以确定因果变异。
