Cytogenetic characterization of swamp (B. bubalis kerebau) and river (B. bubalis bubalis) buffaloes and respective progeny

Abstract

The domestic buffaloes are divided in two groups in agreement with your habitat and karyotype number: the “river buffalos” 2n=50 chromosomes and “swamp buffalos” 2n=48 chromosomes. Is reported also the existence of a karyotype intermediate with 2n=49 chromosomes, what evidences hybridization among the river and swamp buffaloes. This work had as objectives to characterize cytogenetically the buffaloes of the breed Murrah, Carabao and type Baio obtaining the patterns of bands C and G. For that they were obtained preparations metaphases through the cultivation of lymphocytes of blood peripheral in 10 ml RPMI 1640 culture medium. For the breed Murrah and type Baio the chromosomal number is of 2n=50 chromosomes, being the first five pairs morphology metacentric and submetacentric and 20 pairs of chromosomes acrocêntricos including the sexual pairs X and Y. For the breed Carabao the observed number was 2n=48 of the first five pairs metacentric and submetacentric and 19 pairs of chromosomes acrocentric. For both groups the sexual chromosomes X and Y are larger and smaller acrocentric, respectively. Of the animals classified as hybrid, with chromosomal number of 2n=49 they presented five pairs of chromosomes meta/ submetacentric and 20 pairs of chromosomes acrocentric including the sexual chromosomes X larger and Y smaller acrocentric; with some such characteristics as: heteromorphic of the pair 1 and absence of the pair's member 24. The pattern of bands G was obtained for identification of the homologous ones. The constituent heterocromatina revealed demarcation centromeric in every complement and the chromosome Y present C-positive. Therefore, the diploid number 2n=49 are enough for identification of hybrid, while in animals 2n=48 and 2n=50 the first pair's morphologic variation serves as marker to classify them as hybrid.