Failure of XX cells containing the sex reversed gene to produce gametes in allophenic mice.

Allophenic mice have been produced by combining embryos from normal albino mice with embryos of normally pigmented mice carrying the autosomal dominent gene for sex reversed (Sxr) in order to determine the ability of XXSxr cells to differentiate either into sperm or eggs. Sixteen male and six female allophenes have thus far produced more than 1,200 offspring, none of which arose from an XXSxr primordial germ cell. Two allophenic mice were sterile hermaphrodites, and 13 others have yet to be tested. These results indicated that an XX cell is incapable of spermatogenesis even when supplied with the male determining Sxr gene, and that this gene also prevents XX cells from undergoing oogenesis. The latter result contrasts with a previous report of a functional sex reversed oocyte in the mouse.