Genomic Scan for Runs of Homozygosity and Identification of Candidate Genes Under Domestication in Fengjing Pigs

Fengjing pigs are a Chinese native breed known for their high reproductive ability. Runs of homozygosity (ROHs) have emerged as an effective tool for evaluating inbreeding levels and identifying relevant genes in selection. However, the declining population of Fengjing pigs in recent years has raised concerns about inbreeding. Therefore, this study aimed to investigate the ROH patterns, estimate genomic inbreeding levels, and identify candidate genes associated with economic traits using whole-genome resequencing data from 105 Fengjing pigs. A total of 2448 ROHs were identified, with an average of 23.31 ROHs per individual and an average length of 9.50 Mb. The inbreeding coefficient, based on ROHs, was 0.098. Additionally, three genomic regions with a high frequency of ROHs were identified. These regions contained 64 unique genes, including 14 genes associated with important economic traits. Moreover, six overlapping quantitative trait loci (QTLs) and four candidate genes (HSPG2, CDC42, EPHB2, and GRHL3) were identified on Sus scrofa chromosome (SSC) 6. These QTLs are associated with birth traits (health and reproductive efficiency) and meat development traits (meat quality and growth). This study identified many candidate genes and QTLs that overlapped with ROHs and are associated with economically significant traits. These findings can be used in future breeding, conservation, and utilization of specific Chinese native pig breeds.