Due to recent innovations in gene editing technology, great progress has been made in livestock breeding, with researchers rearing gene-edited pigs, cattle, sheep, and other livestock. Gene-editing technology involves knocking in, knocking out, deleting, inhibiting, activating, or replacing specific bases of DNA or RNA sequences at the genome level for accurate modification, and such processes can edit genes at a fixed point without needing DNA templates. In recent years, although clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system-mediated gene-editing technology has been widely used in research into the genetic breeding of animals, the system’s efficiency at inserting foreign genes is not high enough, and there are certain off-target effects; thus, it is not appropriate for use in the genome editing of large livestock such as cashmere goats. In this study, the development status, associated challenges, application prospects, and future prospects of CRISPR/Cas9-mediated precision gene-editing technology for use in livestock breeding were reviewed to provide a theoretical reference for livestock gene function analysis, genetic improvement, and livestock breeding that account for characteristics of local economies.

Background/objectives: Melatonin (MT) promotes secondary hair follicle development and cashmere growth in cashmere goats; however, the underlying molecular mechanisms remain incompletely understood. This study investigated whether MT-associated changes in chi-miR-1388-3p are related to the regulation of cashmere goats dermal papilla cell (DPC) phenotypes through PDGFA , and examined the association of this regulatory axis with MAPK-related factors. Methods: Candidate targets of chi-miR-1388-3p were predicted using the TargetScan database and previously generated transcriptomic data. The direct interaction between chi-miR-1388-3p and the PDGFA 3′ untranslated region (UTR) was evaluated using a dual-luciferase reporter assay. Lentiviral vectors were used to knock down or overexpress chi-miR-1388-3p in DPCs isolated from three independent cashmere goats donors. Each donor was treated as one biological replicate, and technical replicates were averaged before statistical analysis. Cell proliferation, cell-cycle distribution, and apoptosis were assessed using CCK-8 assays and flow cytometry. The expression of PDGFA , MAP3K1 , and FGF21 was examined by quantitative reverse-transcription PCR and Western blotting. MT treatment was performed for 48 h. Results: Chi-miR-1388-3p directly targets the 3′ UTR of PDGFA . Its overexpression can inhibit the proliferation of DPC, increase G0/G1 phase arrest, and increase the apoptosis rate from 9.28% ± 0.17% to 17.61% ± 0.29% ( p < 0.01). Conversely, the inhibition of chi-miR-1388-3p promotes proliferation and reduces the apoptosis rate to 3.07% ± 0.11% ( p < 0.01). The overexpression of chi-miR-1388-3p can significantly reduce the expression levels of PDGFA, MAP3K1 and FGF21 ( p < 0.01), while the inhibitory effect has the opposite effect ( p < 0.01), while inhibition has the opposite effect. MT treatment can decrease the expression of chi-miR-1388-3p, accompanied by changes in DPC proliferation, apoptosis, and PDGFA expression. These results indicate that there is a correlation between the MT/chi-miR-1388-3p/ PDGFA axis and the expression of MAPK-related factors. Conclusion: This study uncovers a novel mechanism by which MT regulates hair follicle growth and provides a foundation for future in vivo studies exploring miRNA-based strategies to enhance cashmere production.

Conventional breeding has a long generation interval; genomic selection can enable early selection and shorten the breeding process in cashmere goats. This study aimed to estimate genomic breeding values for economic traits in Inner Mongolia (Alxa-type) cashmere goats using Bayesian methods. Whole-genome resequencing at 1× depth was performed on 491 Alxa-type cashmere goats (40 males and 451 females), and genotypes were imputed to 10× using a reference panel with an average imputation accuracy of 97.90%. Fixed effects were determined by analysis of variance, and breeding values for body weight, cashmere fiber diameter, and cashmere yield were estimated using Bayes A, Bayes B, and Bayes C; prediction accuracy and unbiasedness were evaluated by five-fold cross-validation. Measurement year and group affected all three traits highly significantly (p < 0.01); sex affected body weight and cashmere yield highly significantly (p < 0.01) but no significant effect on cashmere fiber diameter (p > 0.05); and maternal age had a significant effect on body weight (p < 0.05), but no significant effect on cashmere fiber diameter or cashmere yield (p > 0.05); group had a highly significant effect on all three traits (p < 0.01). Breeding values were estimated using Bayes A, Bayes B, and Bayes C, with five-fold cross-validation, and the three methods performed comparably overall in this population.

Background: Melatonin is an important regulator of seasonal hair follicle activity in Inner Mongolia cashmere goats, but the miRNA-mediated mechanisms linking melatonin signaling to dermal papilla cell (DPC) function remain incompletely understood. In the present study, we examined the role of chi-miR-27a-3p in melatonin-treated DPCs. Methods: DPCs were isolated from Inner Mongolia cashmere goats and treated with melatonin or transduced with lentiviral constructs for chi-miR-27a-3p knockdown or overexpression. Cell proliferation was assessed by CCK8 and Ki67 immunofluorescence, cell-cycle distribution and apoptosis by flow cytometry, and the chi-miR-27a-3p–Wnt7B interaction by dual-luciferase reporter assay; the expression of Wnt7B, Wnt10b, β-catenin, SFRP1 and DKK1 was measured by qRT-PCR and Western blotting. Results: Melatonin treatment was accompanied by downregulation of chi-miR-27a-3p. Chi-miR-27a-3p overexpression reduced DPC proliferation and increased apoptosis, whereas its inhibition increased CCK-8 signal and promoted cell-cycle progression while reducing apoptosis; Ki67 fluorescence was not significantly changed in the knockdown group. Dual-luciferase assays showed that chi-miR-27a-3p directly targets the Wnt7B 3′-UTR in a sequence-dependent manner, and chi-miR-27a-3p manipulation was accompanied by reciprocal changes in Wnt7B, Wnt10b, β-catenin, SFRP1 and DKK1 expression. Conclusions: These findings support a potential regulatory relationship between melatonin, chi-miR-27a-3p and Wnt7B in DPCs; however, whether chi-miR-27a-3p is required for melatonin-induced proliferation and whether Wnt7B mediates its cellular effects require further rescue experiments and in vivo validation.