Background/Objectives: Sterol regulatory element-binding transcription factor 2 (SREBF2) is a key transcription factor involved in regulating cholesterol homeostasis. However, its role in buffalo mammary gland lipid metabolism remains unclear. Methods: To address this, we isolated and characterized the SREBF2 gene from buffalo mammary glands and performed an in-depth analysis of its molecular characteristics, tissue-specific expression, and functional roles in buffalo mammary epithelial cells (BuMECs). Additionally, we investigated the single nucleotide polymorphisms (SNPs) of SREBF2 in both river and swamp buffalo. Results: The coding sequence (CDS) of buffalo SREBF2 is 3327 bp long and encodes a protein of 1108 amino acid residues. Bioinformatics analysis revealed that the molecular characteristics of buffalo SREBF2 were highly similar across Bovidae species, with collinearity being observed among them. An expression profile analysis revealed that SREBF2 is expressed in all 11 tested tissues of buffalo, with its expression level in the mammary gland being higher during lactation than in the dry period. The knockdown of SREBF2 in BuMECs during lactation led to a significant reduction in the expression of genes involved in triglyceride (TAG) and cholesterol synthesis, including PI3K, AKT, mTOR, SREBF1, PPARG, INSIG1, ACACA, SCD, DGAT1, LPL, CD36, HMGCR, and SQLE. This knockdown led to a 23.53% and 94.56% reduction in TAG and cholesterol levels in BuMECs, respectively. In addition, a total of 22 SNPs were identified in both buffalo types, of which four non-synonymous substitutions (c.301G>C, c.304A>T, c.1240G>A, and c.2944G>A) were found exclusively in the SREBF2 CDS of swamp buffalo, and the assessment revealed that these substitutions had no impact on SREBF2 function. Conclusions: These findings emphasize the critical role of SREBF2 in regulating both triglyceride and cholesterol biosynthesis, providing valuable insights into its functions in buffalo mammary glands.

The SCD is a rate-limiting enzyme that catalyzes the synthesis of monounsaturated fatty acids (MUFAs) in dairy cows; however, its role in the mammary gland of buffalo is not well understood. In this study, we isolated and characterized the complete coding sequence (CDS) of the buffalo SCD gene from mammary gland tissue and investigated its effects on milk fat synthesis using bioinformatics analyses, tissue differential expression detection, and cellular functional experiments. The cloned SCD gene has a CDS length of 1080 bp, encoding a protein of 359 amino acids. This protein is hydrophilic, lacks a signal peptide, and contains four transmembrane domains, including 10 conserved motifs and a Delta9-FADS domain, characteristic of the fatty acid desaturase family involved in unsaturated fatty acid biosynthesis within the endoplasmic reticulum. Molecular characterization revealed that the physicochemical properties, conserved domains, structures, and functions of buffalo SCD are highly similar to those in other Bovidae species. Among the tissues analyzed, SCD expression was highest in the mammary gland during lactation and in the cerebellum during dry-off period. Notably, SCD expression in the mammary gland was significantly higher during lactation compared to the dry-off period. Subcellular localization experiments confirmed that SCD functions in the endoplasmic reticulum of buffalo mammary epithelial cells (BuMECs). Functional overexpression and interference experiments in BuMECs demonstrated that SCD promotes milk fat synthesis by affecting the expression of lipid synthesis-related genes such as ACACA, FASN, and DGAT1, as well as milk fat regulatory genes like SREBFs and PPARG, thereby influencing intracellular triglyceride (TAG) content. Additionally, 18 single-nucleotide polymorphisms (SNPs) were identified in the buffalo SCD gene, with a specific SNP at c.-605, showing potential as molecular markers for improving milk production traits. These findings highlight that the SCD gene is a key gene in buffalo milk fat synthesis, involved in the de novo synthesis of milk fatty acids.

Estrogen is a key regulator of skeletal muscle growth and metabolism in birds, yet its specific roles in female chickens remain poorly defined. To address this gap, we established an estrogen-deficient model by surgically removing the ovaries of Wuding hens, a Chinese indigenous slow-growing breed. Growth traits, carcass yield, and meat quality were evaluated across different ages, complemented by histological examination, serum biochemical analysis, and multi-omics approaches (transcriptomics, proteomics, and lipidomics). Ovariectomized hens maintained somatic growth for a longer period and reached greater body weight and carcass yield at 330 days compared with intact controls. Thigh muscle tenderness was also enhanced in the absence of estrogen, despite no long-term differences in muscle fiber morphology. Lipidomic analysis revealed a transient increase in intramuscular triglyceride content at mid-growth (240 days), pointing to altered lipid storage and distribution. Integrated omics profiling further demonstrated significant changes in the mitogen-activated protein kinase (MAPK) and mechanistic target of rapamycin (mTOR) signaling pathways, accompanied by differential expression of key metabolic and structural genes, including mitogen-activated protein kinase 8 (MAPK8), fatty acid binding protein 4 (FABP4), ankyrin 1 (ANK1), and coenzyme Q6 monooxygenase (COQ6). These molecular adjustments suggest that estrogen withdrawal triggers broad reprogramming of muscle signaling and lipid metabolism. Overall, this study highlights the multifaceted role of estrogen in coordinating growth, muscle quality, and lipid homeostasis in hens and provides a functional model for studying estrogen deficiency in poultry with implications for meat quality improvement.

Domestic cattle represent one of the most significant evolutionary successes in the history of human–animal mutualism. This review synthesizes evidence from paleogenomics and modern population genetics, particularly recent pangenome analyses, to reconstruct a comprehensive evolutionary trajectory of cattle. We outline the two domestication events: the emergence of taurine cattle (Bos taurus) in the Fertile Crescent (~10,500 years ago) and zebu cattle (Bos indicus) in the Indus Valley (~8000 years ago). Following domestication, cattle dispersed globally alongside human migration, resulting in a complex genetic mosaic shaped by introgression with wild relatives and extensive admixture between lineages. By integrating data from mitochondrial DNA, Y-chromosome haplotypes, and whole-genome sequencing of modern, ancient, and wild samples, we reconstruct the detailed global dispersal of cattle. Furthermore, we dissect the molecular mechanisms underlying phenotypic diversity, emphasizing how natural selection has driven environmental adaptation, how artificial selection has optimized production traits, and how the emerging bovine pangenome is unveiling “hidden” genetic variations critical for climate resilience and disease resistance. Ultimately, this review summarizes the origin, dispersal, and genomic diversity of cattle, offering vital insights for the conservation of indigenous genetic resources and the advancement of molecular breeding strategies in the face of a changing global climate.

This study investigates the genetic diversity, population structure, and adaptive differentiation of Yunnan native cattle (YNC) using whole-genome SNP data from 457 individuals, representing eight cattle populations and two closely related bovine species (Zhongdian yak and Dulong gayal). Genetic diversity analyses revealed a distinct latitudinal gradient from north to south, with the highest diversity observed in the northern Diqing (DQC) and Zhaotong (ZTC) populations. The observed population structure was largely consistent with geographic distribution, identifying distinct ancestral components and complex admixture patterns. Genome-wide selective sweep scans revealed several key candidate genes underlying local adaptation. Notably, GRIA4 and DUOXA2 were associated with cold tolerance in northern populations, and ST3GAL3 and MST1 were implicated in heat stress adaptation in southern populations. Genome-wide balancing selection analyses further detected significant loci, such as MGST1 and SLC36A1, where divergent haplotype frequencies reflected differential selective pressures on milk-related traits between northern and southern populations. Additionally, we detected signals of historical introgression from Zhongdian yak into DQC cattle, highlighting the introgressed gene SLIT3 as a potential candidate associated with high-altitude thermogenesis. Collectively, these results provide a comprehensive genomic framework for the management and conservation of indigenous bovine genetic resources in Southwest China.

Local chicken genetic resources (LCGRs), representing a unique gene pool shaped by millennia of natural and artificial selection, not only sustain the supply of high-quality protein but also serve as useful biological models for deciphering the evolution of complex traits and environmental adaptability. However, extensive introgression from commercial breeds is causing rapid genetic erosion. Systems biology and multi-omics technologies are reshaping our understanding of the regulatory networks underlying local chicken genetic resources. This review synthesizes four advances. First, at the genomic reference level, long-read sequencing is driving a transition from single linear reference assemblies to high-quality, near-telomere-to-telomere assemblies and graph pangenomes, enabling the unbiased capture of structural variations and microchromosomes. Second, multi-omics studies have begun to integrate association-based evidence across multiple biological layers, including epigenetic variation, single-cell and spatial heterogeneity, cross-tissue metabolic relationships, and host-microbiome interactions. Third, commercial introgression is severe but strongly breed-dependent, affecting 0.64% to 21.52% of the genome across eight Chinese indigenous breeds. We examine how omics findings could be translated into conservation practice by integrating three components into a proposed closed-loop framework: dynamic early-warning monitoring based on effective population size, management of functional variants using a weighted genomic relationship matrix, and primordial germ cell cryopreservation and editing. These components sit at very different levels of evidence, and the complete pipeline has not yet been evaluated longitudinally in any conservation flock. Finally, in the realm of intelligent prediction, the mechanistic attribution provided by explainable artificial intelligence and the zero-shot variant effect prediction capabilities of cross-species genomic foundation models offer two complementary routes, neither of which has yet been applied to a local chicken population. Together, these advances are shifting local chicken genetic resources management from observation-based description toward mechanism-informed decision-making. Rather than reporting an accomplished transition, this review sets out an emerging and feasible roadmap and identifies the evidence gaps that must be closed before it can be implemented.