By growing this so-called primordial oocyte to maturity outside the mouse's body, the scientists have taken a significant step beyond traditional in vitro fertilization (IVF), the test-tube technique in which investigators fertilize an already mature egg with sperm.
Though the follicles hold many thousands of primordial oocytes, only a few hundred will ever produce a mature egg.
As an immediate consequence of their work, Eppig and O'Brien suggest that lab-grown primordial oocytes offer a novel opportunity to study how oocytes develop into mature eggs, to test compounds that may cause birth defects or infertility by damaging oocytes, and to develop new contraceptives.
On a more speculative level, says Eppig, the ability to artificially mature other species' primordial oocytes could provide agricultural breeders and those seeking to protect endangered species with a valuable new way of quickly generating progeny from a specific animal.
Eppig has also had discussions with conservation biologists about whether they could increase the dwindling Florida panther population by using the primordial oocytes of the cats to impregnate closely related panther species.