Estudo do polimorfismo genético da beta-lactoglobulina em bovinos Holando-Gir no Estado de Pernambuco

Abstract

The aim of the present work was to detect the genetic polymorphism of the β-Lactoglobulin (β-Lg) in different groups of Holstein-Gir breed cattle. There was collected 165 animals’ blood samples from the experimental farms of the Instituto Agronômico de Pernambuco (Itambé e Arcoverde) and from a private farm located in Zona da Mata Sul in the state of Pernambuco. The genetic groups were 1/2, 3/4, 5/8 Holstein and 5/8 H 1st, 2nd, 3rd and 4th bi-crossbred generation. For the identification of genotypes, a located fragment was amplified in the areas of exons II and III of β-Lg gene using the PCR technique. The result of the amplification was submitted to the PCR-RFLP analysis to digest the fragment by HaeIII endonuclease and it produced fragments of 400, 220, 190, and 151pb molecular weight for all animals, equivalent to the heterozygous genotype (100% AB) of β-Lg. The Pearson's chi-square test (2)and considering the observed and expected genotypic frequencies of the genotypes β-Lg. Was verified that frequences differed significantly at the level tested (P<0,05), indicating that the samples studied was not in Hardy-Weinberg equilibrium.