Background: Inner Mongolian cashmere goats have hair of excellent quality and high economic value, and the skin hair follicle traits of cashmere goats have a direct and important effect on cashmere yield and quality. Circular RNA has been studied in a variety of tissues and cells.Result: In this study, high-throughput sequencing was used to obtain the expression profiles of circular RNA (circRNA) in the hair follicles of Inner Mongolian cashmere goats at different embryonic stages (45, 55, 65, and 75 days). A total of 21,784 circRNAs were identified. At the same time, the differentially expressed circRNA in the six comparison groups formed in the four stages were: d75vsd45, 59 upregulated and 33 downregulated DE circRNAs; d75vsd55, 61 upregulated and 102 downregulated DE circRNAs; d75vsd65, 32 upregulated and 33 downregulated DE circRNAs; d65vsd55, 67 upregulated and 169 downregulated DE circRNAs; d65vsd45, 96 upregulated and 63 downregulated DE circRNAs; and d55vsd45, 76 upregulated and 42 downregulated DE circRNAs. Six DE circRNA were randomly selected to verify the reliability of the sequencing results by quantitative RT-PCR. Subsequently, the circRNA corresponding host genes were analyzed by the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. The results showed that the biological processes related to hair follicle growth and development enriched by GO mainly included hair follicle morphogenesis and cell development, and the signaling pathways related to hair follicle development included the Notch signaling pathway and NF-κB signaling pathway. We combined the DE circRNA of d75vsd45 with miRNA and mRNA databases (unpublished) to construct the regulatory network of circRNA–miRNA–mRNA, and formed a total of 102 pairs of circRNA–miRNA and 126 pairs of miRNA–mRNA interactions. The binding relationship of circRNA3236–chi-miR-27b-3p and circRNA3236–chi-miR-16b-3p was further verified by dual-luciferase reporter assays, and the results showed that circRNA3236 and chi-miR-27b-3p, and circRNA3236 and chi-miR-16b-3p have a targeted binding relationship.Conclusion: To summarize, we established the expression profiling of circRNA in the fetal skin hair follicles of cashmere goats, and found that the host gene of circRNA may be involved in the development of hair follicles of cashmere goats. The regulatory network of circRNA–miRNA–mRNA was constructed and preliminarily verified using DE circRNAs.

MicroRNA (miRNA) is a type of endogenous short-chain non-coding RNA with regulatory function found in eukaryotes, which is involved in the regulation of a variety of cellular and biological processes. However, the research on the development of cashmere goat secondary hair follicles is still relatively scarce. In this study, small RNA libraries and mRNA libraries of 45 days, 55 days, 65 days, and 75 days of fetal skin of cashmere goats were constructed, and the constructed libraries were sequenced using Illumina Hiseq4000, and the expression profiles of miRNA and mRNA in cashmere goat fetal skin were obtained. The differentially expressed miRNAs and mRNAs in six control groups were identified and the qRT-PCR experiment shows that the sequencing results are accurate. Sixty-six miRNAs related to secondary hair follicle development were screened, and used TargetScan and miRanda to predict 33 highly expressed miRNA target genes. At the same time, 664 mRNAs related to the development of secondary hair follicles were screened, and GO enrichment and KEGG pathway analysis were performed. It was found that some miRNA target genes were consistent with the screening results of mRNAs related to secondary hair follicle development and were enriched in Notch signaling pathway, TGF-β signaling pathway. Therefore, miR-145-5p-DLL4, miR-27b-3p-DLL4, miR-30e-5p-DLL4, miR-193b-3p-TGF-β1, miR-181b-5p-NOTCH2, and miR-103-3p-NOTCH2 regulatory network related to the development of secondary hair follicles were constructed and the results of dual-luciferase reporter gene assay indicated that there is a targeted relationship between chi-miR-30e-5p and DLL4, which will provide a basis for molecular mechanism of miRNA-mRNA in the development of the hair follicles in cashmere goats.

Sheep and goats, among the earliest domesticated animals, hold significant historical importance in Chinese animal husbandry. The rapid advancement of modern biotechnology has rendered genome wide association studies (GWAS) and selection signature analyses have become indispensable tools in livestock genetic research. This review summarizes recent progress in the application of these methods to sheep and goat breeding in China, analyzes existing challenges in the research, and suggests potential research strategies. GWAS and selection signature analyses have identified key genomic regions associated with agronomically important traits. Genes such as LHX2, FGF12 and Notch3 are associated with hair follicle growth and development, while RBM11, SMARCA5 and GAB1 are linked to body size in sheep. Additionally, BMPRIB has been identified as a determinant of reproductive performance and growth rate in both sheep and goats. Despite progress, several challenges remain, including incomplete reference genomes, insufficient phenotypic data, inadequate algorithms, and a lack of functional validation and practical application of findings. Future work must prioritize genomic refinement, the integration of multi-omics, and the development of algorithm. Enhanced international collaboration is crucial to deciphering the genetic basis of key traits, thereby advancing global industry. These initiatives will enable highly precise breeding strategies. Through precise identification and selection of individuals with desirable genetic traits, breeders can significantly enhance the efficiency of genetic improvement. Using Hua sheep 50k chip as an example, it effectively identifies individuals with superior reproductive genes (such as BMPRIB) at an early stage, increases the lambing rate by 27.7%, accelerates the propagation of high-quality breeding groups, provides a large number of breeding sheep with excellent genetic traits for the global sheep industry, and improve the overall quality of germplasm. This will ultimately enhance the sustainable development of global sheep and goat production.

Objective: Dermal papilla is developed from the continuous proliferation and differentiation of dermal fibroblasts, which is the key to the normal development of hair follicles. This study aims to elucidate the role of lncRNA ST6GALNAC3, which is significantly differentially expressed during the secondary hair follicle development stage in cashmere goats, on dermal fibroblasts, and to analyze the regulatory mechanism of this lncRNA thoroughly.Methods: We conducted a screening process and characterization for lncRNAs associated with the development of secondary hair follicles. The effects of lncRNA ST6GALNAC3 on cell proliferation and migration were assessed using CCK8, EdU, and flow cytometry. Subsequently, we employed bioinformatics analysis to identify the target miRNAs of lncRNA ST6GALNAC3 and the corresponding target genes of these miRNAs, respectively, and initially constructed the regulatory axis of lncRNA ST6GALNAC3-chi-miR-24-3p-ID4. Luciferase reporter assays and rescue experiments were performed to confirm the regulatory axis at both molecular and cellular levels, thus elucidating the mechanism by which lncRNA ST6GALNAC3 regulates dermal fibroblasts.Results: One hundred fifty-eight lncRNAs related to secondary hair follicle morphogenesis were identified. Among them, lncRNA ST6GALNAC3 was significantly differentially expressed on embryonic day 75 and significantly inhibited the proliferation and migration of dermal fibroblasts. The results showed that lncRNA ST6GALNAC3 can target chi-miR-24-3p, which in turn can target the ID4 gene. The results of the luciferase reporter assay and rescue assay showed that chi-miR-24-3p binds to both lncRNA ST6GALNAC3 and ID4. Furthermore, lncRNA ST6GALNAC3 can indirectly regulate the proliferation and migration of dermal fibroblasts through chi-miR-24-3p/ID4 axis.Conclusion: LncRNA ST6GALNAC3 inhibits the proliferation and migration of dermal fibroblasts through the chi-miR-24-3p/ID4 axis, thus suppressing the formation of dermal papilla structures and influencing the morphogenesis of secondary hair follicles during embryonic development.

Objective: Inner Mongolia cashmere goats are superior indigenous breeds developed through long-term natural selection and systematic artificial selection, which have experienced a certain intensity of selection pressure during the breeding process, leading to bipolar differentiation trends in cashmere traits. Therefore, identifying genomic selection signatures associated with cashmere traits in Inner Mongolia cashmere goats is crucial for breeding high-quality cashmere-producing goats.Methods: To unravel the genetic basis of cashmere traits, this study stratified 375 Inner Mongolia cashmere goats into eight subgroups based on breeding values for cashmere traits: high-yield vs low-yield cashmere types (HYCG vs LYCG), fine vs coarse cashmere types (FCG vs CCG), long vs short cashmere types (LCG vs SCG), and long vs short fleece types (LFCG vs SFCG). Whole-genome resequencing was performed for genotyping, followed by detection of selection signatures.Results: Results revealed 144, 158, 147, and 147 high-frequency run of homozygosity (ROH) regions in HYCG, FCG, LCG, and LFCG subgroups, respectively, annotating to 515, 565, 510, and 521 genes. Additionally, genomic regions under positive selection were identified using Fst, θπ ratios, and XP-EHH methods, with overlapping regions detected by ≥2 methods defined as candidate regions. Gene annotation identified 777, 660, 712, and 726 candidate genes in HYCG vs LYCG, FCG vs CCG, LCG vs SCG, and LFCG vs SFCG comparisons, respectively. These genes were enriched in 3,051 GO terms and 318 KEGG pathways, including Hippo, MAPK, Wnt, PI3K-Akt, and mTOR signaling pathways associated with cashmere growth and development, involving genes such as LGR6, RUNX2, IGF1R, FGF9, and TCF7L1.Conclusion: In this study, we employed four complementary approaches, including ROHs, Fst, θπ ratios, and XP-EHH, to identify genomic signatures of selection for cashmere traits in Inner Mongolia cashmere goats. These findings provide valuable insights for improving cashmere production performance and developing novel strains with highquality cashmere in Inner Mongolia cashmere goats.

Background:Inner Mongolian cashmere goats have hair of excellent quality and high economic value, and the skin hair follicle traits of cashmere goats have a direct and important effect on cashmere yield and quality.Circular RNA has been studied in a variety of tissues and cells. Result:In this study, high-throughput sequencing was used to obtain the expression profiles of circRNA in the hair follicles of Inner Mongolia cashmere goats at different embryonic stages (45, 55 , 65 and 75 days). A total of 21784 circRNAs were identified. At the same time, the differentially expression circRNA in the six control groups formed in the four stages were: d75vsd45, circRNA up-regulated by 59 and down-regulated by 33; d75vsd55, circRNA up-regulated by 61 and down-regulated by 102; d75vsd65, circRNA up-regulated by 32 and down-regulated by 33; d65vsd55, circRNA up-regulated by 67 and down-regulated by 169; d65vsd45, circRNA up-regulated by 96 and down-regulated by 63; and d55vsd45, circRNA up-regulated by 76 and down-regulated by 42. Six DE circRNA were randomly selected to verify the reliability of the sequencing results by qRT-PCR. Subsequently,the circRNA corresponding host genes were analyzed by GO and the KEGG pathaway. The results showed that the biological processes related to hair follicle growth and development enriched by GO mainly included hair follicle morphogenesis, hair follicle maturation and cell development, and the signal pathways related to hair follicle development included the Notch signaling pathway and NF-kappa B signaling pathway.We combined the DE circRNA of d75vsd45 with miRNA and mRNA databases(unpublished) to construct the co-expression network of circRNA-miRNA-mRNA, and formed a total of 102 pairs of circRNA-miRNA and 126 pairs of miRNA-mRNA interactions. The binding relationship of circRNA3236-chi-miR-27b-3p and circRNA3236-chi-miR-16b-3p was further verified by dual-luciferase reporter assays,and the results showed that circRNA3236 and chi-miR-27b-3p,circRNA3236 and chi-miR-16b-3p have a targeted binding relationship.Conclusion:To summarize, we established the expression profile of circRNA in the fetal skin hair follicles of cashmere goats, and found that the host gene of circRNA may be involved in the development of hair follicles of cashmere goats. The co-expression network of circRNA-miRNA-mRNA that DE circRNA was constructed and preliminary verification was carried out.