The fate of XO germ cells in the testes of XO/XY and XO/XY/XYY mouse mosaics: evidence for a spermatogenesis gene on the mouse Y chromosome.

A cytogenetic and histological study of nine XO/XY or XO/XY/XYY mosaic mice revealed that XO germ cells were selectively eliminated from the spermatogenic epithelium. Although the XO contribution to the bone marrow in seven mice exceeded 50%, in only two cases were significant numbers of dividing XO spermatogonia present. These XO germ cells only occasionally progressed to meiosis and then degenerated prior to first meiotic metaphase. It was concluded that the mouse Y chromosome carries a "spermatogenesis gene" (or genes) which acts autonomously in the germ cells.