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MicroRNAs (miRNAs) regulate the development and growth cycle of hair follicles (HFs). The molecular mechanism by which miRNAs determine the development of HFs in the sheep foetus remains elusive. In this study, the expression profiles of miRNAs at 11 development periods (45, 55, 65, 75, 85, 95, 105, 115, 125, 135 and 145 d) in sheep foetus skin were analysed by high-throughput sequencing and bioinformatics analysis. A total of 72 conserved miRNAs, 44 novel miRNAs and 32 known miRNAs were significantly differentially expressed. qRT-PCR results for 18 miRNAs were consistent with the sequencing data. 85 d of foetal development was the starting point for secondary hair follicle (SF) development according to tissue morphology and cluster analysis. In SF development, the prolactin signalling pathway and platelet activation played important roles, and 10 miRNAs were potential candidate miRNAs in SF initiation.

Integrin linked kinase (ILK) is a scaffold protein, which plays important roles in hair follicle development. The cDNA sequence of novel ILK gene in sheep was cloned by PCR method and analyzed by bioinformatics. Tissue expression profiling in eight tissues and temporal profiling at different wool follicle anagen stages in skin was analyzed. The results showed that the whole open reading frame (ORF) of ILK gene was 1 359 bp in length, which encoded 452 amino acids. Bioinformatic analysis indicated that the secondary structure of ILK gene was mainly made up of three ankyrin repeats and a kinase domain, and there were multiple phosphorylation and Protein Kinase C sites in this gene. The RT-PCR result confirmed that ILK mRNA was expressed in heart, liver, spleen, lung, skeletal muscle, skin, and small intestine, and the expression level was much higher in skin, spleen, and liver than others. The q-PCR analysis demonstrated that the ex-pression level of ILK was significantly increased from March to May (early follicle anagen initiation) in both sheep breeds, Chinese Merino and Kazakh sheep, and there were certain differences from June to October between the two breeds. The above results indicated that ILK gene may play key roles in regulating secondary follicle growth.

The purpose of this experiment was to explore the monthly dynamic changes of yield and nutrient components of temperate desert-steppe type rangeland and temperate steppe-desert type rangeland on the northern slope of Tianshan Mountains in Xinjiang, and the effects of grazing on the weight changes of multiple Suffolk ewes and weaned lambs under the conditions of two grassland types. Suffolk postpartum ewes with a similar weight of two years old and 120 lambs after weaning were randomly divided into two groups. Each group had three repetitions, and each repetition had 20 sheep. Group A lambs and Group C ewes were grazed in temperate desert-steppe type rangeland experimental area (type I grass group, namely Festucasulcata, feather grass and Seriphidium kaschgaricum), while Group B lambs and Group D ewes were grazed in temperate steppe-desert type rangeland experimental area (type II grass group, namely Seriphidium borotalense Ling et Y. R. Ling, Kochia prostrata and Carex turkestanica). The trial period was 120 days. The results showed that in June and September, the fresh grass yield of type I grass group was significantly higher than that of type II grass group (P<0.05). In September, the hay yield of type I grass group was significantly higher than that of type II grass group (P<0.05). In June, the dry-fresh ratio of type I grass group was significantly lower than that of type II grass group (P<0.05). In June and September, the crude ash content of type I grass group was significantly lower than that of type II grass group ( P<0.05). In July, the crude protein content of type I grass group was significantly higher than that of type II grass group (P<0.05), and in September, the crude protein content of type I grass group was significantly lower than that of type II grass group (P<0.05). The content of nitrogen-free extracts of type I grass group in June was significantly higher than that in September (P<0.05). In June, July and September, the phosphorus content of type II grass group was significantly higher than that of type I grass group (P<0.05). There was no significant difference in total weight gain, average daily weight gain, and relative weight gain between the two grazing grassland types (P>0.05). The weaned lamb weight increased continuously, and the litter size, litter weight, and weaned weight of ewes in the following year had no significant difference (P>0.05). The results showed that with the increase of temperature and the decrease of precipitation, the forage yield of the two grazing grassland types decreased first and then increased, and the forage nutrition level decreased. The grazing adaptability and stress resistance of multiple Suffolk sheep were better under extreme environmental conditions. [ABSTRACT FROM AUTHOR]

Understanding the genetic changes underlying phenotypic variation in sheep (Ovis aries) may facilitate our efforts towards further improvement. Here, we report the deep resequencing of 248 sheep including the wild ancestor (O. orientalis), landraces, and improved breeds. We explored the sheep variome and selection signatures. We detected genomic regions harboring genes associated with distinct morphological and agronomic traits, which may be past and potential future targets of domestication, breeding, and selection. Furthermore, we found non-synonymous mutations in a set of plausible candidate genes and significant differences in their allele frequency distributions across breeds. We identified PDGFD as a likely causal gene for fat deposition in the tails of sheep through transcriptome, RT-PCR, qPCR, and Western blot analyses. Our results provide insights into the demographic history of sheep and a valuable genomic resource for future genetic studies and improved genome-assisted breeding of sheep and other domestic animals. Genetic resources for livestock are valuable for understanding their demography and past selection, and may inform future breeding programs and agricultural improvement. Here, the authors present deep resequencing of 248 wild and domestic sheep, with associated data and analysis. [ABSTRACT FROM AUTHOR]