Polymorphism of Nramp1 Gene and Its Association with Diarrhea in Pigs

Abstract

Background: Natural resistance associated macrophage protein 1 (Nramp1) is a relatively conservative gene that plays a crucial role in swine immune response and disease resistance. Methods: We identified the polymorphisms and gene variations in the exon 2 of Nramp1 using polymerase chain reaction–restriction fragment length polymorphism and investigated the correlation between the polymorphisms and piglet diarrhea in four pig breeds (Bamei, Duroc, Landrace, and Large White pigs). Result: The results showed that two alleles (A and B) were identified in all the pig breeds, three genotypes (AA, BB, and AB) were detected in Bamei and Large White breeds, and two genotypes (AA and AB) were detected in Landrace and Duroc breeds. Allele A and genotype AB were dominant in Bamei, Large White, and Landrace breeds, whereas genotype AA was dominant in Duroc pigs. A moderate polymorphism was observed in Landrace and Large White pigs, and polymorphism was abundant in Bamei pigs and low in Duroc pigs. The Chi-square test for Hardy–Weinberg equilibrium disclosed that the exon 2 of Nramp1 in the four breeds of pigs did not deviate from the Hardy–Weinberg balance (P less than 0.05). The results of association analysis showed a significant correlation between breed and piglet diarrhea (P less than 0.05), and the diarrhea score of Bamei pigs was much lower than those of the other breeds. The study could supply theoretical references for further functional research on Nramp1 gene and for screening genes related to disease-resistance breeding.