Oogenesis in Adult Mice and Starlings

Abstract

IT has long been the general assumption that, at least in the higher vertebrates, the stock of oogonia and oocytes laid down in the ovaries during embryonic life is never afterwards increased, and that in the adult the waves of maturing eggs are derived from this stock which lasts the animal throughout its active sexual life. In 1923 this theory was challenged by Allen¹, who had observed in the ovary of the adult mouse (Mus musculus L.) the formation of new oogonia from the mitotic divisions of the cells of the germinal epithelium. Depending on the plane of division, these mitoses resulted in the production either of new cells in the germinal epithelium or of new oogonia. Although the original theory is still widely held, much evidence confirming Allen's observations has now accumulated, and a review of present knowledge has been given by Swezy².