Genome sequencing
We sampled a total of 28 cattle, from four different regions of China (Mongolia, Yanbian, Hainan and Yunnan). DNA was extracted from the blood of each individual and degradation was monitored based on its concentration by spectrometry, fluorometry, and 1% agarose gel electrophoresis. Paired-end libraries with insert size of 150 bp were constructed for each individual and sequenced using the a HiSeq X Ten Sequencing System (Illumina Inc., San Diego, CA, USA). We mapped the clean reads after filtering sequencing data to the Bos Taurusgenome assembly (version UMD_3.1.1) using BWA [49]. All the potential single-nucleotide polymorphisms site (SNPs) were extracted and filtered by GATK [50]. ANNOVAR [51] and existing Genome annotation file (GFF/GTF) made corresponding annotations on the detected SNPs. All experimental procedures were performed in accordance with the Regulations for the Administration of Affairs Concerning Experimental Animals approved by the State Council of People’s Republic of China.