Author : Saney Songsri

Summary : The purpose of this study was to analyze the chromosomes of two major types of water buffaloes, the Murrah or river type and the carabao or swamp type, and their F1, BC1 (carabao) and BC2 (carabao) hybrids.

The diploid chromosomes number of the Philippine and Thai carabaos consists of 48 chromosomes, of which 6 are metacentric, 4 submetacentric and the rest acrocentric, including the sex chromosomes. The Murrah buffalo has 2n = 50 chromosomes, of which 4are metacentric, 6 submetracentric and the rest acrocentric, including sex hormones. The F1, BC1 (carabao) hybrids have 2n = 49 chromosomes, and the smallest acrocentric chromosome (chromosome 24) is unpaired. In each type of animals, the X-chromosome is the largest acrocentric, and the Y-chromosome is also acrocentric.

The morphological characteristics of the chromosomes of the Murrah buffalo and the carabao are very similar, except for chromosome 1 which is metacentric and longer in the carabao, but is submetacentric and shorter in the Murrah buffalo. Thus,except for chromosome 1 and chromosome 24, it is not possible to trace the origin of the chromosomes in F1, BC1 (carabao) and BC2 (carabao).

The differences in the chromosome number as well as the morphology of chromosome 1 of the Murrah buffalo (river type) and that of the carabao (swamp type) are additional proofs in support of the classification of the carabao as Babalus carabanensis as proposed by Castillo (1971).