Comparative Studies on the Chromosomes of Five Species of Cattles of the Genus Bos in China

This paper presents the comparative studies of the karyotypes of five cattle species.The chromosome number of Bos taurus,B.grunniens and B.indicus are all 2n=60,while those of B.frontalis and B.gaurus readei are 2n=58 and 2n=56 respectively.The diploid numbers and chromosomal morphology of the five species have been compared each other.B.taurus and B.grunniens seem to have the same karyotype.The karyotype of B.indicus differs both from that of B.taurus and that of B.grunniens only in the presence of the subacrocentric Y.Bos frontalis has a diploid number of 2n=58 with one pair of metacentric autosome.B.gaurus readei possesses the lowest diploid number (2n=56) in the five species of cattles examined.Its karyotype is different from other species because of the presence of two pairs of submetacentric autosomes.Finally,the possibility of hybridization among five species of cattles is discussed from the point of view of cytogenetics.