ABNORMAL STRUCTURE OF THE Y-CHROMOSOME DETECTED IN BOVINE GONADAL HYPOPLASIA (XY FEMALE) BY FISH

The structure of the Y chromosome was investigated by FISH and G bandi ng in 3 cases of bovine XY females shown by PCR to lack the SRY gene. Although 2 different repeat-DNA sequences (BC1.2 and btDYZ-1) hybridiz ed to the short arm of the Y chromosome in a normal bull, they hybridi zed to both arms of the Y chromosome in the XY females. In the Y chrom osome from XY females, only the centromeric region was darkly stained by G banding, in comparison with dark staining on the long arm of a no rmal Y chromosome. From the results obtained, it seemed that the Y chr omosome from the XY females was structurally abnormal, namely an isoch romosome with an identical short arm. Our results also confirm that SR Y is located on the long arm of the Y chromosome in bovine.