LOCALIZATION OF THE ALPHA-S2-CASEIN GENE (CASAS2) TO THE HOMOEOLOGOUSCATTLE, SHEEP, AND GOAT CHROMOSOMES-4 BY IN-SITU HYBRIDIZATION

The alpha-S2-casein gene (CASAS2) has been mapped to the homoeologous cattle, sheep, and goat chromosomes 4 and to the long arm of a bovine chromosome translocation, t(4;8), using nonradioactive in situ hybridi zation and simultaneous fluorescent R-banding. The t(4;8) has been cha racterized by GTG-, GBG-, and RBG-banding and by silver staining of nu cleolus organizer regions. These results confirm the previous (ISCNDA, 1989) localization of the casein gene group to chromosome 4 of cattle , sheep, and goats. We propose that the discrepancy between our result s and earlier assignments of the casein gene group to chromosome 6 of cattle and sheep can be explained by the fact that the chromosome iden tified as No. 6 in the Reading Conference (1976) report was renamed ch romosome 4 in the ISCNDA (1989) standardized karyotype of both species .