The Hulunbuir short-tailed sheep (Ovis aries) is a breed native to China, in which the short-tail phenotype is the result of artificial and natural selection favoring a specific set of genetic mutations. Here, we analyzed the genetic differences between short-tail and normal-tail phenotypes at the genomic level. Selection signals were identified in genome-wide sequences. From 16 sheep, we identified 72,101,346 single nucleotide polymorphisms. Selection signals were detected based on the fixation index and heterozygosity. Seven genomic regions under putative selection were identified, and these regions contained nine genes. Among these genes, T was the strongest candidate as T is related to vertebral development. In T, a nonsynonymous mutation at c.G334T resulted in p.G112W substitution. We inferred that the c.G334T mutation in T leads to functional changes in Brachyury—encoded by this gene—resulting in the short-tail phenotype. Our findings provide a valuable insight into the development of the short-tail phenotype in sheep and other short-tailed animals.

The microbial community performs vital functions in the intestinal system of animals. Modulation of the gut microbiota structure can indirectly or directly affect gut health and host metabolism. Aohan fine-wool sheep grow in semi-desert grasslands in China and show excellent stress tolerance. In this study, we amplified 16S rRNA gene to investigate the dynamic distribution and adaptability of the gut microbiome in the duodenum, jejunum, ileum, cecum, colon, and rectum of seven Aohan fine-wool sheep at 12 months. The results showed that the microbial composition and diversity of the ileum and the large intestine (collectively termed the hindgut) were close together, and the genetic distance and functional projections between them were similar. Meanwhile, the diversity index results revealed that the bacterial richness and diversity of the hindgut were significantly higher than those of the foregut. We found that from the foregut to the hindgut, the dominant bacteria changed from Proteobacteria to Bacteroidetes. In LEfSe analysis, Succiniclasticum was found to be significantly abundant bacteria in the foregut and was involved in succinic acid metabolism. Ruminococcaceae and Caldicoprobacteraceae were significantly abundant in hindgut, which can degrade cellulose polysaccharides in the large intestine and produce beneficial metabolites. Moreover, Coriobacteriaceae and Eggthellaceae are involved in flavonoid metabolism and polyphenol production. Interestingly, these unique bacteria have not been reported in Mongolian sheep or other sheep breeds. Collectively, the gut microbiota of Aohan fine-wool sheep is one of the keys to adapting to the semi-desert grassland environment. Our results provide new insights into the role of gut microbiota in improving stress tolerance and gut health in sheep.

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Precise characterization of biological processes critical to proliferation and metastasis of colorectal cancer should facilitate the development of diagnostic and prognostic biomarkers as well as novel treatments. Using mRNA-Seq, we examined the protein coding messenger RNA (mRNA) expression profiles across different histologically defined stages of primary colon cancers and compared them to their patient matched normal tissue controls. In comparing 79 colorectal cancers to their matched normal mucosa, tumors were distinguished from normal non-malignant tissues not only in the upregulation of biological processes pertaining to cell proliferation, inflammation, and tissue remodeling, but even more strikingly, in downregulated biological processes including fatty acid beta oxidization for ATP production and epithelial cell differentiation and function. A network analysis of deregulated genes revealed newly described cancer networks and putative hub genes. Taken together, our findings suggest that, within an inflammatory microenvironment, invasive, dedifferentiated and rapidly dividing tumor cells divert the oxidation of fatty acids and lipids from energy production into lipid components of cell membranes and organelles to support tumor proliferation. A gene co-expression network analysis provides a clear and broad picture of biological pathways in tumors that may significantly enhance or supplant current histopathologic studies.

Context Wool is one of the most important animal fibres for the textile industry, and its diameter directly affects its economic value. However, the molecular mechanisms underlying wool fibre diameter (FD) in sheep have not been fully elucidated. Aims The aims of the work were to make an initial comparison of skin transcriptomes from sheep with wool of high and low FD, and to identify key genes affecting FD. Methods High-throughput RNA-Seq technology was employed to explore the skin transcriptome, using three sheep with fine wool (FD <21.0 μm) and three sheep with coarse wool (FD >27.0 μm). Key results We obtained 28607228 bp of clean sequence data, 78.9% (±3.8%) of which uniquely aligned to the reference genome across the six samples. In total, 19914 mRNA transcripts were expressed (FPKM >0) in the six skin samples, among which were certain well-known genes involved in the skin–hair cycle, such as KRTAP7-1, KRT14, Wnt10b, Wnt2b, β-catenin and FGF5. Furthermore, 467 genes were significantly differentially expressed between the fine-wool and coarse-wool groups, including 21 genes with upregulated and 446 genes with downregulated expression in the sheep with lower FD. These differentially expressed genes were particularly enriched in the gene ontology processes related to lipid metabolism, skin development, differentiation and immune function (P < 0.05). The biological processes were involved in collagen catabolism, negative regulation of macromolecule metabolism, steroid hormone stimulation and lipid metabolism. A significant Kyoto Encyclopedia of Genes and Genomes pathway involving the metabolism of lipids and lipoproteins was also enriched, revealing that lipid metabolism might be one of the key factors affecting FD. The expression of these differentially expressed genes that were involved in the metabolism of lipids and lipoproteins pathway was verified by quantitative real-time PCR (qPCR). The correlation between the mRNA expression level from qPCR and RNA-Seq data was 0.999 (P < 0.001). Conclusions The 467 differentially expressed genes, especially those involved in lipid metabolism and immune function, may play key roles in wool follicle metabolism and the expression of wool FD. Implications This study provided valuable data for future studies aimed at elucidating the mechanisms that underlie wool follicle metabolism and wool FD. The work may also have implications for studies of the human hair follicle.