Cytogenetics of wild boars from commercial breeders in Southern and Southeastern Brazil

Abstract

Wild boar breeding in Brazil frequently faces difficulties, such as the acquisition of pure animals (2n = 36), that is, which are not descendants of the wild boar and domestic swine crossings. The purposes of this work were the cytogenetic characterization of the wild boar (Sus scrofa scrofa L.) and the determination of the karyotypic frequency of different genetic groups. One thousand, three hundred and eight wild boars from three genetic groups from the southern and southeastern regions of Brazil were studied. The sample consisted of male and female animals aged 5.5 to 30 months. They showed a diploid number (2n) of 36 (46.71%), 37 (39.68%) and 38 (13.61 %) chromosomes. The data were submitted to statistical analysis through the Fisher's Exact Test. According to the C banding technique, all the chromosomes of the analyzed animals with three diploid numbers showed positive C band at the centromere region and only chromosome Y was almost entirely heterochromatic. However, in NOR banding, two pairs of metacentric chromosomes were stained at the secondary constrictions close to the centromere, corresponding to pairs 7 and 10 in 2n = 36, 37 and 38 animals. The presence of a medium submetacentric chromosome t (15; 17), formed by robertsonian fusion in the animals with 2n = 37 can differentiate hybrid pure wild boars and from "javaporcos" as they are phenotypically very similar.