BACKGROUND/OBJECTIVES: β-defensins are a family of classical endogenous antimicrobial peptides involved in innate immune response. β-defensins are encoded by a large number of loci and known to show extensive copy number variations (CNVs) that may be useful as DNA markers for host resilience against pathogenic infections.

METHODS

We developed a quantitative PCR-based method to estimate the genomic copy numbers of 13 pig β-defensin () genes and analyzed the range and extent of CNVs across several commercial pig breeds.

RESULTS

We assessed 38 animals from four pure breeds and a crossbreed and observed CNVs ranging from two to five genomic copies from , , , , , and , indicating extensive individual variations of gene copy numbers of these genes within each breed. The mean copy numbers of these s were lower in Landrace and higher in Berkshire than in other breeds. We also observed a strong correlation between the genomic copy number and their expression levels with the correlation coefficient () > 0.9 for , , and in the kidney, with these genes being highly expressed.

CONCLUSIONS

Although we only analyzed 13 s among 29 reported genes, our results showed the presence of extensive CNVs in β-defensins from pigs. The genomic copy number of β-defensins may contribute to improving animal resilience against pathogenic infections and other associated phenotypes.