A complex pattern of microsatellite polymorphism within the bovine NRAMP1 gene

Nucleotide sequence polymorphism due to a variation in the number of GT din ucleotide repeats was found in the 3' untranslated region (nucleotide posit ions 1781-1804) of the bovine natural resistance-associated macrophage prot ein (NRAMP1) gene. The total variation in the number of GT repeats resulted not only from changes in the number of GT repeats but also from variation in the number of 5' adjacent Gs. Two types of event may explain the polymor phism recently termed 'allelic homoplasy' (Grimaldi & Crouau-Roy, 1997). Be sides addition and/or deletion of GT repeats, a T vs. G transversion at pos ition 1782 at the 5' end of the GT repeat array generated variability in 3' UTR of the bovine NRAMP1 gene. Another substitution site (G-->A), interrup ting the GT repeat array at position 1805, previously reported in cattle an d not found in related species, was nor found to show within-species polymo rphism. Although the functional significance of the polymorphism reported r emains unknown, its detection allows investigation of associations with res istance and/or susceptibility to important intracellular pathogens in cattl e.