LAUSR

ABSTRACT Fat deposition and distribution in different body sites are associated with livestock productivity. In some sheep breeds, fat is excessively accumulated around the tail region, which is regarded as the fat-tail phenotype. Though some plausible genes or genomic regions associated with the fat-tail phenotype were identified, further validation of them in different individuals and breeds is still required. In this study, we implemented differential expression analysis using RNA-seq data in longissimus dorsi muscle tissue (MUT), perirenal adipose tissue (PAT) and tail adipose tissue (TAT) of Hu sheep, which is a representative of short fat-tailed sheep. The result identified 1336, 427 and 665 differentially expressed genes (DEGs) in MUT, PAT and TAT of Hu sheep respectively. Of those, 600 DEGs and 336 DEGs showed unique expression in TAT and PAT, respectively. In addition, integrated analyses of our data with published data from small-tailed Han sheep, Guangling large-tailed sheep and Tan sheep found 9 DEGs in PAT and 13 DEGs in TAT of Hu sheep have similar expression patterns in the remaining three sheep breeds. Among 9 DEGs in PAT, WT1, TCF21, PPFIBP1 and WNT10B may have important roles in perirenal adipose formation. Among 13 DEGs in TAT, PKD2L1 and MST1 may play significant roles in the maintenance of unsaturated fatty acid content in TAT. Five genes that were previously reported to be correlated with tailed fat deposition were further validated in current study, including CITED1, HOTAIR_2, HOTAIR_3, HOXC12 and HOXC13. Furthermore, we also investigated the expression pattern of 42 candidate genes identified by selection signature analysis or genome wide association analysis from published studies. Two of them were found to be highly expressed in TAT, including PPP1CA and PEX6. Our findings identify candidate genes for tail fat deposition across different breeds and pave a solid foundation for studying the regulation of fat deposition in sheep in the future.