A DNA POLYMORPHISM FROM 5 INBRED STRAINS OF THE MOUSE IDENTIFIES A FUNCTIONAL CLASS OF DOMESTICUS-TYPE-Y CHROMOSOME THAT PRODUCES THE SAME PHENOTYPIC DISTRIBUTION OF GONADAL HERMAPHRODITES

The wild-derived CLA inbred strain of the house mouse contains a domesticus-type Y chromosome that lacks a 2.3-kb TaqI band with fragment 1 of the AC11 probe. The CLA Y chromosome also causes a low frequency of XY gonadal hermaphrodites when backcrossed to the C57BL/6J strain (F.G. Biddle and Y. Nishioka. 1988. Genome, 30: 870-878). A similar domesticus-type Y chromosome, lacking the 2.3-kb TaqI band has now been found in the four historical inbred strains AKR/J, MA/MyJ, PL/J, and RF/J. When backcrossed to C57BL/6J, these four Y chromosomes cause low frequencies of gonadal hermaphrodites similar to the CLA Y and phenotypic distributions of types of gonad are indistinguishable from that with the CLA Y. The absence of the 2.3-kb TaqI band appears to be a polymorphism among domesticus-type Y chromosomes that identifies one of the three functional classes that, so far, can be distinguished only by their effects on testis differentiation in backcross test fetuses with the C57BL/6J strain. Three other historical inbred strains, BUB/BnJ, ST/bJ, and SWR/J, with a domesticus-type Y chromosome but containing the 2.3-kb TaqI band, were also assayed. They permit normal testis development in backcross test fetuses with C57BL/6J.