Large-Scale Comparative Genomics of European and Chinese Cattle Breeds Reveals Population Structure, Breeding...

Modern cattle comprise two major evolutionary lineages: intensively selected commercial breeds and locally adapted native populations. To investigate their genomic divergence, we performed a comparative population genomic analysis by integrating whole-genome resequencing (WGS) data from multiple representative native breeds and major European commercial breeds. Population genetic analyses showed clear phylogenetic separation between the two groups, with distinct patterns of genetic diversity. Chinese native cattle exhibited generally higher nucleotide diversity (π), lower inbreeding levels, and geographically structured admixed ancestry. Comparative analyses of selection signatures identified 886 candidate selected genes in European commercial breeds, which were primarily enriched in pathways related to production traits, including protein turnover, reproductive regulation, lipid metabolism, and neuro-regulation. In contrast, 50 candidate selected genes in Chinese native cattle were significantly enriched in nervous system functions, particularly ligand-gated ion channel activity and chloride transport (e.g., GRID2, GLRA2/4, GABRD), suggesting neural/ionic regulation may contribute to local adaptation alongside other polygenic mechanisms. Additionally, the two groups also differed in patterns of deleterious mutation load. These findings indicate partially distinct evolutionary trajectories between "production-optimized" and "environment-adapted" cattle and highlight the value of conserving the genetic diversity and adaptive alleles of Chinese native cattle.