MAPPING OF THE NATURAL RESISTANCE-ASSOCIATED MACROPHAGE PROTEIN-1 (NRAMP1) GENE TO PIG CHROMOSOME-15

The natural resistance-associated macrophage protein 1 (NRAMP1) was ma pped in the pig for study as a potential candidate gene in controlling pig resistance to Salmonella infection. Primers were designed from th e pig cDNA to amplify a 1.6 kb fragment between exons 1 and 3. By usin g a pig-rodent somatic cell hybrid panel, NRAMP1 was mapped to pig chr omosome 15 (SSC15) with 100% probability, and the regional assignment was SSC15q23-26 with 87% concordance. A polymerase chain reaction-rest riction fragment length polymorphism (PCR-RFLP) marker was developed b y using the HinfI enzyme and three alleles were identified from a popu lation including 11 breeds. Linkage analysis confirmed the physical as signment by using the PiGMaP reference families. Pig NRAMP1 was linked to SSC15 markers S0088, S0149 and S0284 (LOD > 3). A small population study revealed large allele frequency differences among tested breeds . An A allele is only observed in darn (white) lines whereas a similar exclusivity of the C allele was seen in sire (colored) breeds.