Association between single nucleotide polymorphisms in p53 and abortion in Thoroughbred mares

Single nucleotide polymorphisms (SNPs) in the p53 gene have been studied extensively in humans. The aims of this study were to determine the frequency of the Arg/Pro SNP in p53 in Thoroughbred mares on one stud in Brazil and to correlate p53 genotypes with reproductive performance. SNPs were detected by PCR-restriction fragment length polymorphism in blood samples from 105 horses and confirmed by sequencing. The allele frequency in Thoroughbred mares at codon 72 in exon 4 was 73.3% Arg/Pro, 17.1% Arg/Arg and 9.6% Pro/Pro. The presence of Arg/Pro was significantly associated with abortion (P = 0.02), while Pro/Pro mares had a lower probability of abortion (P < 0.05). Using a logistic regression model, the dominance effect was significant (P = 0.044; odds ratio 7.94) for abortion and additive effects were not significant (P = 0.26). p53 may play a role in equine reproduction.