GENETIC AND PHYSICAL MAPPING OF THE NATURAL RESISTANCE-ASSOCIATED MACROPHAGE PROTEIN-1 (NRAMP1) IN CHICKEN

The chicken natural resistance-associated macrophage protein 1 (NRAMP1 ) gene has been mapped by linkage analysis by use of a reference panel to develop the chicken molecular genetic linkage map and by fluoresce nce in situ hybridization. The chicken homolog of the murine Nramp1 ge ne was mapped to a linkage group located on Chromosome (Chr) 7q13, whi ch includes three genes (CD28, NDUSF1, and EF1B) that have previously been mapped either to mouse Chr 1 or to human Chr 2q. Physical mapping by pulsed-field gel electrophoresis revealed that NRAMP1 is tightly l inked to the villin gene and that the genomic organization (gene order and presence of CpG islands) of the chromosomal region carrying NRAMP 1 is well conserved between the chicken and mammalian genomes, The reg ions on mouse Chr 1, human Chr 2q, and chicken Chr 7q that encompass N RAMP1 represent large conserved chromosomal segments between the mamma lian and avian genomes. The chromosome mapping of the chicken NRAMP1 g ene is a first step in determining its possible role in differential s usceptibility to salmonellosis in this species.