Sex reversal in XY mice caused by dominant mutation on chromosome 17.

A Y-linked gene(s) is undoubtedly a prerequisite for testicular development in mammals. However, exceptional cases suggest that the mere presence of the Y chromosome or the Y-linked testis-determining gene does not totally control the fate of the bipotential gonad. For example, in the mouse, a major as yet unmapped autosomal locus is necessary for normal testicular development and at least one additional autosomal locus is implicated. We present here a third autosomal sex-determining locus. This dominantly inherited trait, tentatively named T-associated sex reversal (gene symbol Tas), is closely linked to or a part of the T/t complex on chromosome 17 of the mouse. Gonads of chromosomally XY individuals who inherit Tas on the C57BL/6J inbred strain background differentiate as ovaries or ovotestes.