Department of Molecular Biology and Genetics, Center for Quantitative Genetics and Genomics, Aarhus University, DK-8830, Tjele, Denmark.
BMC Genet. 2020 Jan 31;21(1):9. doi: 10.1186/s12863-020-0810-4.
Infrared spectral analysis of milk is cheap, fast, and accurate. Infrared light interacts with chemical bonds present inside the milk, which means that Fourier transform infrared milk spectra are a reflection of the chemical composition of milk. Heritability of Fourier transform infrared milk spectra has been analysed previously. Further genetic analysis of Fourier transform infrared milk spectra could give us a better insight in the genes underlying milk composition. Breed influences milk composition, yet not much is known about the effect of breed on Fourier transform infrared milk spectra. Improved understanding of the effect of breed on Fourier transform infrared milk spectra could enhance efficient application of Fourier transform infrared milk spectra. The aim of this study is to perform a genome wide association study on a selection of wavenumbers for Danish Holstein and Danish Jersey. This will improve our understanding of the genetics underlying milk composition in these two dairy cattle breeds.
For each breed separately, fifteen wavenumbers were analysed. Overall, more quantitative trait loci were observed for Danish Jersey compared to Danish Holstein. For both breeds, the majority of the wavenumbers was most strongly associated to a genomic region on BTA 14 harbouring DGAT1. Furthermore, for both breeds most quantitative trait loci were observed for wavenumbers that interact with the chemical bond C-O. For Danish Jersey, wavenumbers that interact with C-H were associated to genes that are involved in fatty acid synthesis, such as AGPAT3, AGPAT6, PPARGC1A, SREBF1, and FADS1. For wavenumbers which interact with -OH, associations were observed to genomic regions that have been linked to alpha-lactalbumin.
The current study identified many quantitative trait loci that underlie Fourier transform infrared milk spectra, and thus milk composition. Differences were observed between groups of wavenumbers that interact with different chemical bonds. Both overlapping and different QTL were observed for Danish Holstein and Danish Jersey.
牛奶的红外光谱分析既便宜、快速又准确。红外光与牛奶内部的化学键相互作用，这意味着傅里叶变换红外牛奶光谱是牛奶化学成分的反映。之前已经分析了傅里叶变换红外牛奶光谱的遗传性。对傅里叶变换红外牛奶光谱进行进一步的遗传分析，可以让我们更好地了解牛奶成分背后的基因。品种会影响牛奶成分，但我们对品种对傅里叶变换红外牛奶光谱的影响知之甚少。更好地了解品种对傅里叶变换红外牛奶光谱的影响，可以增强傅里叶变换红外牛奶光谱的有效应用。本研究的目的是对丹麦荷斯坦牛和丹麦泽西牛的一组波数进行全基因组关联研究。这将提高我们对这两个奶牛品种牛奶成分遗传基础的理解。
分别对每个品种进行了十五个波数的分析。总体而言，与丹麦荷斯坦牛相比，丹麦泽西牛观察到的数量性状基因座更多。对于这两个品种，大多数波数与 BTA14 上包含 DGAT1 的基因组区域最强相关。此外，对于这两个品种，大多数数量性状基因座都观察到与 C-O 化学键相互作用的波数。对于丹麦泽西牛，与 C-H 相互作用的波数与参与脂肪酸合成的基因如 AGPAT3、AGPAT6、PPARGC1A、SREBF1 和 FADS1 相关。对于与-OH 相互作用的波数，观察到与已与α-乳白蛋白相关的基因组区域存在关联。
本研究确定了许多数量性状基因座，这些基因座是傅里叶变换红外牛奶光谱的基础，也是牛奶成分的基础。与不同化学键相互作用的波数组之间存在差异。在丹麦荷斯坦牛和丹麦泽西牛中观察到重叠和不同的 QTL。
