Construction of multi-tissue transcriptome map and analysis of tissue-specific genes in Tan sheep

The genetic regulatory mechanisms underlying key economic traits in Tan sheep remain unclear. To systematically analyze gene expression patterns across multiple tissues in Tan sheep, this study selected 20 male Tan sheep aged 6 months from the same rearing background. Tissue samples were collected from the heart, liver, spleen, lung, kidney, longissimus muscle, perirenal fat, and tail fat, and conducted transcriptomic sequencing to construct a multi-tissue transcriptomic atlas of Tan sheep and analyze gene expression patterns across multiple tissues. Multi-tissue expression profiling analysis indicates that tissues with similar physiological functions exhibit a high degree of clustering in their gene expression patterns. The study identified a total of 8,257 low-variation genes, 1,473 medium-variation genes, and 2,983 high-variation genes. Among these, low-variation genes exhibit highly conserved functions and are primarily enriched in critical biological processes such as RNA transport, protein processing, and the mTOR signaling pathway. Additionally, 1,790 tissue-specific genes were identified, with their enriched pathways closely associated with tissue function. WGCNA analysis identified 16 gene modules highly associated with specific tissues, revealing the core regulatory gene networks in each tissue. RT-qPCR was used to validate SLC22A8, LOC101120535, AICDA, and TAT as tissue-specific genes in the heart, kidney, lung, and muscle, respectively. In summary, the multi-tissue transcriptomic atlas of Tan sheep constructed in this study systematically analyzed the expression characteristics of tissue-specific genes, providing important data support for a deeper understanding of the genetic regulatory networks underlying the formation of economic traits in Tan sheep.