关键词: 牦牛, 低氧适应, 肺脏, 转录组

Abstract: This study was aimed to explore the characteristics and regularity of gene expression of yaks adapting to high-altitude hypoxic environment. Transcriptome sequencing was performed in 2.5-3-year-old healthy male Maiwa yaks bred at high and low altitudes for 4 months. The average altitudes were 3 560 m and 478 m, respectively. Lungs of yaks were sequenced by RNA-Seq technology using Illumina II High-throughput Sequencing Platform (HiSeqTM 2500/4000). Then, the expressions of differentially expressed genes in lungs of yaks were verified by qRT-PCR. The results indicated that there were approximately 576, 610 million Clean Reads in lung transcriptome of yaks bred in high and low altitudes, respectively. The numbers of reads mapped to the reference genome accounted for more than 91.74% and 91.28% percentages, respectively. And 2 047 new transcripts were discovered in lung RNA-Seq. There were 199 differentially expressed genes (DEGs) between the two test groups, including 89 up-regulated DEGs and 110 down-regulated DEGs. The differentially expressed genes were enriched in 297 GO terms and 146 KEGG pathways, which contained 62 GO terms and 35 KEGG pathways related to hypoxic adaptation. The cell adhesion, protein complex and calcium ion binding were the largest proportions of biological processes, cellular component and molecular function in hypoxia-related GO terms. Meanwhile, TNF signaling pathway were the largest proportion of KEGG pathways related to hypoxia, followed by HIF-1 signaling pathway. In addition, qRT-PCR results showed that the expressions of HLA-DOA, HLA-DRA, C2 and MASP1 were consistent with those of RNA-Seq. This study will benefit for a global and in-depth understanding of gene expression of yak lung response to high altitude hypoxia.

Key words: Yaks, Hypoxic adaptation, Lung, Transcriptomics