Comprehensive analysis of lncRNA and mRNA expression changes in Tibetan chicken lung tissue between three developmental stages

The Tibetan chicken is a native Chinese breed that lives at high elevations and has adapted to the extreme environmental conditions of the Tibetan Plateau. However, its hypoxic adaptation at the gene expression level is unclear. Here, we sequenced nine lung transcriptomes of the Tibetan chicken at three developmental stages (5 and 42 weeks and 4.5 years). A total of 1.02 billion clean reads were obtained. We identified 16 012 mRNAs and 6898 lncRNAs. The expression of mRNA showed that nine samples were significantly divided into three clusters, with higher correlation and closer relationship between the 5 and 42 week groups. We identified 399 differentially expressed genes (DEGs) between the 5 and 42 week groups, 3532 DEGs between the 5 week and 4.5 year groups, and 3909 DEGs between the 42 week and 4.5 year groups. The up-regulated DEGs in the 5 week group, compared with 42 week and 4.5 year groups, were enriched in GO terms associated with growth and development, whereas the up-regulated DEGs in the 4.5 year group were mainly enriched in many metabolic-related categories. Moreover, the enrichment results with up-regulated DEGs in the 5 and/or 42 week groups, compared with the 4.5 year group, were associated with hypoxic adaptation, such as oxygen transport, oxygen binding and oxygen carrier activity, and calcium signaling pathway. In addition, we identified 978 high-correlation lncRNA and protein-coding gene pairs, and 524 significant neighboring protein-coding genes were also DEGs. Our results provide new insights into gene expression of lung tissue in Tibetan chickens during the aging process.