Is there a germ plasm in mouse oocytes?

It was found that in the Graafian oocytes of laboratory mice Mus musculus the population of electrondense bodies contains two patterns of structures. One of these, designated as cortical granules, originated from the Golgi complex and was surrounded by a membrane. The other was discovered as cristae-containing mitochondrial derivatives lacked an outer membrane. It was found that the mitochondrial derivatives underwent progressive condensation and transformed into electron-dense bodies similar to germinal bodies of metazoan animals. Based on examination of Graafian follicle oocytes from 5 female individuals, about 15% of electron-dense bodies were cortical granules. However, about 85% of electrondense bodies were condensing mitochondrial derivatives transforming into electron-dense bodies.