Genome-Wide Association Study Revealed Key Genes with the Teat Number in Jishen Black Pigs

As an important reproductive trait, teat number plays a vital role in the pork industry, which is related to the ability of sows to host more piglets. However, the genetic mechanism of the teat number in pigs is still not very clear. We collected phenotype data, including the total teat number (TTN), left teat number (LTN), and right teat number (RTN), from 300 Jishen Black (JSB) sows and performed genotyping using a porcine SNP 50K panel. Most JSB sows exhibited 14, 15, or 16 TTN (259, 86%). Only 41 pigs (14%) had TTN values outside this range. Moreover, the LTN and TTN exhibited approximate frequency distribution in the studied population. Seven was the most common LTN and RTN in JSB sows, accounting for 181 (60%) and 173 (57%), respectively. Additionally, these traits exhibited low-to-medium heritability (0.14–0.22). Using the BLINK and FarmCPU models, three, six, and three key loci were identified in the GWAS of TTN, LTN, and RTN, respectively. Additionally, five key genes were detected to play vital roles in teat number traits, including ME1, SCN8A, EVC, UBC, and PDE4D. Our research provided efficient molecular markers and new insights into further improvement and understanding for teat number traits in Jishen Black pigs.