Genomic and transcriptomic analyses reveal selection of genes for puberty in Bama Xiang pigs

The Bama Xiang pig (BMX) is a famous early-maturing Chinese indigenous breed with a two-end black coat. To uncover the genetic basis of the BMX phenotype, we conducted comparative genomic analyses between BMX and East Asian wild boars and Laiwu pigs, respectively. Genes under positive selection were enriched in pathways associated with gonadal hormone and melanin synthesis, consistent with the phenotypic changes observed during development in BMX pigs. We also performed differentially expressed gene analysis based on RNA-seq data from pituitary tissues of BMX and Large White pigs. The CTTNBP2NL, FRS2, KANK4, and KATNAL1 genes were under selection and exhibited expressional changes in the pituitary tissue, which may affect BMX pig puberty. Our study demonstrated the positive selection of early maturity in the development of BMX pigs and advances our knowledge on the role of regulatory elements in puberty evolution in pigs.