Tp(Y)1Ct^Sxr-b

At least five loci map to the Tp(Y)1Ct segment: Hya, Spy, Tdy, Zfy1, and Zfy2. The Tp(Y)1CtSxr-b variant retained the testis determining gene, Sry, but lost the H-Y antigen-determining gene, Hya. This chromosomal variant also appears to lack one of the Y-linked zinc finger genes, Zfy1 but retains the other, Zfy2. The formation of Tp(Y)1CtSxr-b from Tp(Y)1CtSxr-a was later shown to be due to unequal crossing over between Zfy1 and Zfy2, resulting in a fusion gene and a small interstitial deletion. XX females carrying this transposition variant are sex-reversed but do not express Y Chromosome linked transplantation antigen, Hya. (J:9332)