Caracterização e comparação citogenética dos bubalinos carabao, murrah e tipo baio

Abstract

In order to detect any chromosomal abnormalities, both structural and numerical, Carabao (swamp buffalo), Murrah and type Baio (river buffalo) were analyzed cytogenetically. Blood samples of the Carabao and type Baio were taken from specimens belonging to Embrapa Eastern Amazon (PA) since the Murrah samples are from the Embrapa Temperate Climate (RS). After cell culture completion, the chromosomal analysis was performed, where Carabao had the lowest number (2n=48, XX/XY), while type Baio and Murrah had the same diploid number (2n=50, XX/XY). In karyotyping three hybrid individuals were identify, who were listed as Carabao. These presented two important features in its karyotype: heteromorphism of the first pair and absence of a member of the pair 24. Among Murrah breed, a female presented heteromorphism in sexual pair (XX). Biometrics proved the difference in size of the first chromosome pair, in the case of the hybrid, and the heteromorphism of the X sexual pair from Murrah. Moreover, biometrics for Carabao chromosomes reveled a higher than average compared to type Baio and Murrah. The G banding revealed a higher number of dark bands, rich in AT, for Baio, while the Carabao presented a higher frequency of lighter bands, rich in CG. The C banding reveled similar markings in the three subspecies, and chromosomes were marked at the centromeres. The type Baio showed a distal marker of constitutive heterochromatin in the sex chromosome X. The nucleolus organizing regions were identified in the telomeric regions in five chromosome pairs in the Carabao and six pairs in type Baio.