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 (CSN1S2) were mapped to river buffalo (Bubalus bubalis L.) and cattle (Bos taurus L.) chromosomes by fluorescence in situ hybridization (FISH) and R-banding. Clear probe hybridization signals were detected on river buffalo chromosome 7q, band 32, and the homologous cattle chromosome. These mapping data allow the indirect assignment of the entire cattle U15 syntenic group to river buffalo chromosome 7. The assignment of U15 to river buffalo chromosome 7 is discussed in the light of chromosomal nomenclature discrepancies involving the homologous cattle chromosome.