Allele distribution and testing for association between an oxygen dependent degradation domain SNP in EPAS1 and pulmonary arterial pressures in yearling Angus cattle

Abstract

At altitudes >1500 m, measurements of mean pulmonary arterial pressures (mPAP; mmHg) are a measure of pulmonary hypertension (PH) in cattle. Genotypes of a G/A single nucleotide polymorphism (SNP; rs208684340) in the endothelial PAS domain protein 1 (EPAS1) gene were determined for mPAP categories (low, moderate, high) on Angus cattle. The A allele of this SNP was postulated to be associated with altitude-induced PH. The first objective was to estimate allele and genotypic frequencies in Angus cattle at high- (elevation 1850 to 2800 m) and low-altitude (elevation 91 to 1192 m) ranches (n = 118; random sample of 1275). Percent of cattle at these low elevation ranches with genotypes G/G, G/A, and A/A were 64.4, 33.9, and 1.7%, respectively, and a minor allele frequency (MAF; A allele) of 18.6%. Bulls, steers, and heifers (n = 691) from 4 high-altitude Angus herds in Colorado and Wyoming were genotyped. Percent of cattle with genotypes G/G, G/A, and A/A were 48.6, 34.3, and 17.1%, respectively, with a MAF of 34.2%. Average mPAP was 40.5 ± 8.8 mmHg. Low, moderate, and high-mPAP category MAF were similar (χ² = 3.03; P = 0.22), with values of 35.4, 31.0, and 37.8%, respectively. Additionally we sought to evaluate the genotype-to-phenotype association of this SNP with mPAP phenotypes (n = 532) from the Colorado State University Beef Improvement Center (elevation 2150 m) Angus herd. Linear mixed model analysis suggested genotype was not a predictor (P = 0.61) of mPAP. Results do not suggest the A allele of SNP in EPAS1 is associated with high altitude-induced PH in yearling Angus cattle.