Chromosome banding homologies in Swamp and Murrah buffalo

Silver staining of Swamp buffalo (2n = 48) metaphase chromosomes revealed telomeric nucleolus organizer regions (NOR's) located on five pairs of autosomes identified by R-banding as numbers 4 p (submetacentric), 8, 20, 22, and 23 (acrocentrics); interphase nuclei also showed no more than five nucleoli. The Murrah buffalo (2n = 50) was previously reported to have telomeric NOR's located on six pairs, -3 p and 4 p (submetacentric), 8, 21, 23, and 24 (acrocentrics). By comparing the two types of buffalo it was concluded that: all of the chromosomes are similar in banding patterns; chromosome 1 of Swamp results from a telomere-centromere tandem fusion between two chromosomes identified as 4 p and 9, respectively, in the Murrah karyotype, thus accounting for the reduced diploid number of Swamp buffalo; the fusion causes the loss of NOR's on the telomeres of chromosome 4, thus accounting for the reduced number of NOR chromosome pairs of Swamp; the presence of a pale C-band are in the region of junction between chromosome 4 and 9 involved in the fusion suggests that the centromeric region of the later is retained and altered.