Caracterização do polimorfismo e associação dos genes da kappa-caseína e da beta-lactoglobulina com a produção de leite em bovinos da raça Girolando

Abstract

Candidate genes of the kappa-casein (CSN3) and beta-lactoglobulin (LGB) are involved in the composition, processing and quality of milk and are linked to production characteristics. This study aimed to evaluate the allele and genotype frequencies of kappa-casein gene (CSN3) and beta-lactoglobulin (LGB) and associate them with milk production of cattle participants Progeny Test Breed Girolando through analysis of variables milk yield in 305 days (P305) and predicted transmitting ability (PTA) for milk. For the study of polymorphisms were genotyped sires 138 and 729 cows (n = 867) for CSN3 and 737 and 131 bulls and cows (n = 868) to LGB. For the association analysis were evaluated 127 bulls and 536 cows (n = 663) and 127 for CSN3 bulls and 536 cows (n = 663) for LGB. The differentiation of allele A / B genes studied was obtained by PCR-RFLP. Allele frequencies, genotype and calculating the probability of Hardy-Weinberg equilibrium (HWE) were established through the program Popgen versão1.32 and tested by χ ² test at a significance level of 1%. The association study was performed by regression analysis using the GLM procedure of SAS 9.1. The allele and genotype frequencies for the gene CSN3 were, respectively, 0.7324 (AA), 0.2468 (AB) 0.0208 (BB) and 0.8558 (A) 0.1442 (B) and the LGB were, respectively, 0.2604 (AA), 0.4827 (AB) 0.2569 (BB) and 0.5017 (A) 0.4983 (B). The population is in HWE for both genes. No association was found between genes evaluated and analyzed variables.