Study of GH and IGF-1 genes’ polymorphism in Holstein cows in Uruguay

Abstract

In this study, 308 cows were genotyped for AluI (GH) and SnabI (IGF-I) polymorphisms and allelic and genotypic frequencies were determined in Holstein cows from four farms of Uruguay. For the GH gene, the L allele was the most frequent in the three dairies sampled (0.821, 0.853 and 0.947), while the V allele was found in low or very low frequency in farms 1, 2 and 4 (0.179, 0.147 and 0.053), leading to a high frequency of the LL genotype. The IGF-I gene showed a more balanced distribution of alleles: allele A = 0.609, 0.592, 0.554 and 0.547; allele B = 0.391, 0.408, 0.446 and 0.453, for farms 1, 2, 3 and 4, respectively. Low and moderate values of heterozygosis were obtained (minimum value Ho = 0.105 for GH in farm 4; maximum value Ho = 0.554 for IGF-I in the same population). In addition, FIS values were low to moderate and no deviations from Hardy-Weinberg equilibrium were detected. Global FST values were very close to zero (FST < 0.009) arguing in favor of observed genetic similarity between populations, being farm 1 and 4 the most distant populations with a FST 0.022.