Different eggs in adolescent girls, adult women

Professor Liu's team used two genetically modified mouse models to show that the first wave of eggs, which starts immediately after birth, contributes to the onset of puberty and provides fertilizable eggs into the transition from adolescence to adulthood. In contrast, the adult wave remains in a state of dormancy until activated during the adult life and then provides eggs throughout the entire reproductive lifespan.

This is the first time that the developmental dynamics of two distinct populations of eggs have been clearly described in an animal model, and there is evidence that these two waves of eggs most likely also exist in the human ovary. The identification and characterization of the two waves of eggs will lead to new ways of thinking about how to obtain the best eggs when treating women for ovarian diseases that cause infertility. Such techniques will prove especially useful for women suffering from premature ovarian failure (POF), which affects 1%-4% of all women of childbearing age. The results may also lead to more effective treatments for ovarian diseases by specifically targeting the different egg populations.