The use of Y-chromosome-specific repeated DNA sequences in the analysis of testis development in an XX/XY mouse.

A study, by means of Y-chromosome-specific repeated DNA probes, of mouse (ST) with small testes is reviewed. Mouse ST was shown to be a somatic mosaic of 10% XY and 90% XX cells. The cellular composition of the azoospermic testis reflected the overall proportions of XX and XY cells but it was found that XY cells predominated in the Sertoli cells of the testis tubules. These findings have been interpreted to indicate a fundamental role for the Sertoli cell in inducing testis organization in the indifferent gonadal rudiment, involving the expression of the Y chromosome.