Surgical castration can effectively avoid boar taint and improve pork quality by removing the synthesis of androstenone in the testis, thereby reducing its deposition in adipose tissue. The expression of genes involved in testis-derived hormone metabolism was altered following surgical castration, but the upstream regulatory factors and underlying mechanism remain unclear. In this study, we systematically profiled chromatin accessibility and transcriptional dynamics in liver tissue of castrated and intact full-sibling Yorkshire pigs. First, we identified 897 differentially expressed genes and 6864 differential accessible regions (DARs) using RNA- and ATAC-seq. By integrating the RNA- and ATAC-seq results, 227 genes were identified, and a significant positive correlation was revealed between differential gene expression and the ATAC-seq signal. We constructed a transcription factor regulatory network after motif analysis of DARs and identified a candidate transcription factor (TF) SP1 that targeted the HSD3B1 gene, which was responsible for the metabolism of androstenone. Subsequently, we annotated DARs by incorporating H3K27ac ChIP-seq data, marking 2234 typical enhancers and 245 super enhancers involved in the regulation of all testis-derived hormones. Among these, four typical enhancers associated with HSD3B1 were identified. Furthermore, an in-depth investigation was conducted on the androstenone-related enhancers, and an androstenone-related mutation was identified in a newfound candidatetypical enhancer (andEN) with dual-luciferase assays. These findings provide further insights into how enhancers function as links between phenotypic and non-coding area variations. The discovery of upstream TF and enhancers of HSD3B1 contributes to understanding the regulatory networks of androstenone metabolism and provides an important foundation for improving pork quality.

Tibetan pigs are an important indigenous genetic resource on the Qinghai-Tibetan Plateau, but their population history remains unclear. Here, we analyzed whole-genome resequencing data from 29 Tibetan pigs and 69 wild boars from different regions to investigate their genetic structure and origin. Population structure analyses showed that Tibetan pigs formed a distinct genetic cluster, but clear substructure was present among the four Tibetan pig groups. Demographic analyses indicated that all Tibetan pigs shared a similar deep ancestral background, whereas the Tibetan population from Tibet (TT) showed a distinct recent demographic trajectory relative to the other Tibetan pig groups. Model inference based on multidimensional site frequency spectra further supported a mixed origin of TT from northern and southern Asian wild boar-related ancestral components. In contrast, the other three Tibetan pig groups were best explained as lineages derived from TT after its formation. We also detected a persistent western Eurasian-related excess-sharing signal in TT, consistent with potential introgression. Selection scans identified candidate genes and pathways potentially related to hypoxia adaptation, cardiovascular function, and lung development.