Data_Sheet_1_Comparative Transcriptome Analysis of Key Genes and Pathways Activated in Response to Fat Deposition in Two Sheep Breeds With Distinct Tail Phenotype.ZIP

Fat tail in sheep presents a valuable energy reserve that has historically facilitated adaptation to harsh environments. However, in modern intensive and semi-intensive sheep industry systems, breeds with leaner tails are more desirable. In the present study, RNA sequencing (RNA-Seq) was applied to determine the transcriptome profiles of tail fat tissues in two Chinese sheep breeds, fat-rumped Altay sheep and thin-tailed Xinjiang fine wool (XFW) sheep, with extreme fat tail phenotype difference. Then the differentially expressed genes (DEGs) and their sequence variations were further analyzed. In total, 21,527 genes were detected, among which 3,965 displayed significant expression variations in tail fat tissues of the two sheep breeds (P < 0.05), including 707 upregulated and 3,258 downregulated genes. Gene Ontology (GO) analysis disclosed that 198 DEGs were related to fat metabolism. In Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, the majority of DEGs were significantly enriched in “adipocytokine signaling,” “PPAR signaling,” and “metabolic pathways” (P < 0.05); moreover, some genes were involved in multiple pathways. Among the 198 DEGs, 22 genes were markedly up- or downregulated in tail fat tissue of Altay sheep, indicating that these genes might be closely related to the fat tail trait of this breed. A total of 41,724 and 42,193 SNPs were detected in the transcriptomic data of tail fat tissues obtained from Altay and XFW sheep, respectively. The distribution of seven SNPs in the coding regions of the 22 candidate genes was further investigated in populations of three sheep breeds with distinct tail phenotypes. In particular, the g.18167532T/C (Oar_v3.1) mutation of the ATP-binding cassette transporter A1 (ABCA1) gene and g.57036072G/T (Oar_v3.1) mutation of the solute carrier family 27 member 2 (SLC27A2) gene showed significantly different distributions and were closely associated with tail phenotype (P < 0.05). The present study provides transcriptomic evidence explaining the differences in fat- and thin-tailed sheep breeds and reveals numerous DEGs and SNPs associated with tail phenotype. Our data provide a valuable theoretical basis for selection of lean-tailed sheep breeds.

羊的肥尾蕴含着宝贵的能量储备，这一特性在历史上有助于其适应恶劣环境。然而，在现代集约化和半集约化的羊产业系统中，更倾向于选择尾部较瘦的品种。在本研究中，通过RNA测序（RNA-Seq）技术，对两种中国羊品种——脂肪臀型的阿尔泰羊和细尾的新疆细毛羊（XFW）——具有极端肥尾表型的尾部脂肪组织进行了转录组学分析。随后，对差异表达基因（DEGs）及其序列变异进行了进一步研究。共检测到21,527个基因，其中3,965个基因在两种羊品种的尾部脂肪组织中表现出显著的表达差异（P < 0.05），包括707个上调和3,258个下调的基因。基因本体（GO）分析揭示，198个DEGs与脂肪代谢相关。在京都基因与基因组百科全书（KEGG）通路分析中，大多数DEGs显著富集于“脂肪细胞因子信号传导”、“PPAR信号传导”和“代谢途径”（P < 0.05）；此外，某些基因参与了多个通路。在198个DEGs中，22个基因在阿尔泰羊的尾部脂肪组织中显著上调或下调，这表明这些基因可能与该品种的肥尾性状密切相关。在阿尔泰羊和XFW羊的尾部脂肪组织的转录组数据中，分别检测到41,724个和42,193个单核苷酸多态性（SNPs）。进一步调查了三种具有不同尾部表型羊品种的22个候选基因编码区域中的7个SNPs的分布。特别是，ATP结合盒转运蛋白A1（ABCA1）基因的g.18167532T/C（Oar_v3.1）突变和溶质载体家族27成员2（SLC27A2）基因的g.57036072G/T（Oar_v3.1）突变显示出显著不同的分布，且与尾部表型密切相关（P < 0.05）。本研究提供了转录组学证据，解释了肥尾和瘦尾羊品种之间的差异，并揭示了与尾部表型相关的众多DEGs和SNPs。我们的数据为选择瘦尾羊品种提供了宝贵的理论基础。