Germ Cells in XX ↔ XY Mouse Chimeras
Despite the fact that cells of both genetic sexes coexist in sex-chromosome chimeras, the sexual differentiation of these individuals tends to be canalized into a male (predominantly) or a female direction, rather than leading to a hermaphroditic condition. This creates an opportunity for approaching the problem of whether or not the germ cells of the mouse can undergo functional sex reversal. Up to the time when experimental mouse chimeras became available (Tarkowski 1961; Mintz 1962), this question remained unanswered, because all attempts to reverse sexual differentiation in placental mammals were unsuccessful. Since then, results obtained by breeding XX ↔ XY mouse chimeras have led to the conclusion that the XX chromosomal constitution precludes differentiation of germ cells into spermatozoa; and they have provided some evidence that the XY constitution may be compatible with oogenesis.
KeywordsSexual Differentiation Primordial Germ Cell Meiotic Prophase Male Germ Cell Mouse Chimera
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