季节性发情是限制绵羊高效生产的主要瓶颈，若能从遗传上改变绵羊季节性发情的特性，则可增加母羊年产胎次，维持羔羊肉的全年稳定生产。然而绵羊常年发情性状的分子机制和主效基因尚未明确。本研究将以小尾寒羊（常年发情）和滩羊（季节性发情）为实验材料，分析滩羊乏情期与2种绵羊发情季节激素水平的差异；利用RNA-seq技术筛选乏情期与发情季节滩羊间、乏情期滩羊与同季节小尾寒羊间松果体和繁殖组织中差异表达的基因、miRNA和lncRNA，选择基因功能聚类为繁殖或昼夜节律相关类别且基因和差异miRNA间存在靶关系的组合，利用过表达和敲除的方法在细胞水平揭示它们的生物学功能；结合基因和miRNA数据预测新lncRNA的功能；构建绵羊常年发情和季节性发情相关基因-miRNA-lncRNA的共表达调控网络。本研究可为揭示绵羊常年发情分子机制提供重要线索，为通过分子手段选育常年发情绵羊品种提供依据和基因来源。

Seasonal estrus is a main bottleneck restricting the efficient production in sheep industry. If the ovine seasonal estrus would be changed using genetic methods, the annual parities of ewes will increase and the stable production of mutton will be maintained throughout the year. However, the molecular mechanism and major genes for ovine year-round estrus are still unclear. In this study, the Small Tail Han (STH) sheep (year-round estrous breed) and Tan sheep (seasonal estrous breed) are selected as test breeds. The hormone levels between Tan sheep in anestrus and two breeds in estrous seasons will be compared. By transcriptome sequencing technology (RNA-seq), the differentially expressed genes, miRNAs and lncRNAs in pineal body and reproductive tissues will be screened between Tan sheep in anestrus and STH sheep in the same season, and between Tan sheep in anestrus and in estrous season. The differentially expressed genes, which are categorized into reproduction or circadian rhythms clusters by GO enrichment analysis and also targets of miRNAs selected above, and their corresponding miRNAs will be focused on and their biological functions will be further analyzed at cellular level by over-expression and knockout of genes. The functions of new lncRNAs will be predicted by combining the results of genes and miRNAs. The gene-miRNA-lncRNA co-expression regulatory network related to ovine year-round or seasonal estrus will be constructed. This research will provide important clues for revealing the molecular mechanism of ovine year-round estrus, and offer a theoretical basis and some key genes for breeding of year-round estrous sheep by molecular techniques.