| ovine progressive pneumonia provirus levels are unaffected by the prion 171r allele in an idaho sheep flock. | selective breeding of sheep for arginine (r) at prion gene (prnp) codon 171 confers resistance to classical scrapie. however, other effects of 171r selection are uncertain. ovine progressive pneumonia/maedi-visna virus (oppv) may infect up to 66% of a flock thus any affect of 171r selection on oppv susceptibility or disease progression could have major impact on the sheep industry. hypotheses that the prnp 171r allele is 1) associated with the presence of oppv provirus and 2) associated with hig ... | 2009 | 19284685 |