Mao X, Sahana G, De Koning D-J, Guldbrandtsen B
J Anim Sci. 2016 Apr;94(4):1426-37. doi: 10.2527/jas.2015-9838.
Male calves and culled cows of dairy cattle are used for beef production. However, unlike beef breeds, the genetics of growth performance traits in dairy breeds have not been extensively studied. Here, we performed a genome-wide association study (GWAS) on Holsteins ( = 5,519), Jerseys ( = 1,231), and Red Dairy Cattle ( = 4,410) to identify QTL for growth traits. First, a GWAS was performed within breeds using whole-genome sequence variants. Later, a meta-analysis was performed to combine information across the 3 breeds. We have identified several QTL that have large effects on growth traits in Holsteins and Red Dairy Cattle but with little overlap across breeds. Only 1 QTL located on chromosome 10 was shared between Holsteins and Red Dairy Cattle. The most significant variant (BTA10:59,164,533, rs43636323; -value = 2.8 × 10) in this QTL explained 2.4% of the total additive genetic variance in Red Dairy Cattle. The gene is a strong candidate for the underlying gene of this QTL. In Red Dairy Cattle, a QTL near 25 Mb on chromosome 14 was very significantly associated with growth traits, consistent with the previously reported gene , which affects growth in beef cattle and humans. No QTL for growth performance was statistically significant in Jerseys, possibly due to the low power of detection with the small sample size. The meta-analysis of the 3 breeds increased the power to detect QTL.
雄性犊牛和淘汰的奶牛用于牛肉生产。然而，与肉牛品种不同，奶牛品种生长性能性状的遗传学尚未得到广泛研究。在此，我们对荷斯坦奶牛（n = 5519）、泽西奶牛（n = 1231）和红安格斯奶牛（n = 4410）进行了全基因组关联研究（GWAS），以鉴定生长性状的数量性状位点（QTL）。首先，利用全基因组序列变异在各品种内进行GWAS分析。随后，进行荟萃分析以整合3个品种的信息。我们已经鉴定出几个对荷斯坦奶牛和红安格斯奶牛生长性状有较大影响的QTL，但品种间重叠较少。荷斯坦奶牛和红安格斯奶牛之间仅共享1个位于10号染色体上的QTL。该QTL中最显著的变异（BTA10:59,164,533，rs43636323；P值 = 2.8×10⁻⁹）解释了红安格斯奶牛总加性遗传方差的2.4%。该基因是此QTL潜在基因的有力候选者。在红安格斯奶牛中，14号染色体上靠近25 Mb处的一个QTL与生长性状极显著相关，这与先前报道的影响肉牛和人类生长的基因一致。在泽西奶牛中未检测到对生长性能有统计学显著意义的QTL，可能是由于样本量小导致检测效能低。对这3个品种的荟萃分析提高了检测QTL的效能。
