FISH MAPPING OF THE ALPHA-S2 CASEIN GENE ON RIVER BUFFALO AND CATTLE CHROMOSOMES IDENTIFIES A NOMENCLATURE DISCREPANCY IN THE BOVINE KARYOTYPE

A mixture of five genomic clones spanning the alpha-S2 casein gene (CS N1S2) were mapped to river buffalo (Bubalus bubalis L.) and cattle (Bo s taurus L.) chromosomes by fluorescence in situ hybridization (FISH) and R-banding. Clear probe hybridization signals were detected on rive r buffalo chromosome 7q, band 32, and the homologous cattle chromosome . These mapping data allow the indirect assignment of the entire cattl e U15 syntenic group to river buffalo chromosome 7. The assignment of U15 to river buffalo chromosome 7 is discussed in the light of chromos omal nomenclature discrepancies involving the homologous cattle chromo some.