Estudo de polimorfismo dos genes da αS1-caseína e da ĸ-caseína em cabras do semi-árido do Nordeste brasileiro

Abstract

The goat raising, by the socio-economic expression that it represents for the population of the Northeast region, has the necessity of biotechnology implantation in order to improve the productivity of its herd. The study of genetic polymorphism of the milk of the animals raised in zoosanitary bioclimatology conditions of this region will permit a better correlation with the breed for reproduction and the knowledge of the milk composition of goats of different breeds. Aiming at the genotyping of Moxotó goats breed and mixed-breed goats from the Semi-Arid of Brazilian Northeast (Pernambuco, Paraíba, Ceará and Rio Grande do Norte), by means of PCR-RFLP technique (Polymerase Chain Reaction-Restriction Fragment Lenght Polymorfism), it was studied the polymorphism of the αS1-casein and ĸ-casein genes. It was collected total blood samples from adult Moxotó and mixed-breed goats, female, healthy, raised extensively; the leucocytary DNA extraction was made through chloroform and phenol protocol and the genes were ampReaction) with specific primers for each casein. After that, it was used XmnI enzymes(αS1-casein) and HaeIII (ĸ-casein) to obtain the pattern of fragments representing the B and D allele, being the majority of the animals presenting the BB genotype, while the D one appeared in a smaller number, associated to B (B/D). Among the animals of Moxotó breed, the allelic frequency observed was 96,03% for the genotype BB and 3,97% for the genotype B/D. In relation to the mixed-breed animals, the frequency was 88,77% and 11,23% for the genotypes BB and B/D, respectively. It was not observed statistic difference between the breeds nor the studied States. In the case of ĸ-casein, only the allele A was found, characterizing the monomorphism for all the animals studied. Based in the results of the present study, it is demonstrated a genetic proximity between Moxotó and mixed-breed of the exiting herd in the states of the Northeast included in this research, characterizing a similar origin of these animals. Before the detection of a higher presence of the allele B (strong) of the αS1-casein gene in thelified using the PCR technique (Polymerase Chainanimals studied, it is acknowledged the possibility that phenotypically these animals come to show the characteristic of a strong protein production, an important one for the milk destined to cheese production, favoring the goat raising in the region.