Reproductive aging: insights from model organisms.

Aging was once thought to be the result of a general deterioration of tissues as opposed to their being under regulatory control. However, investigations in a number of model organisms have illustrated that aspects of aging are controlled by genetic mechanisms and are potentially manipulable, suggesting the possibility of treatment for age-related disorders. Reproductive decline is one aspect of aging. In model organisms and humans of both sexes, increasing age is associated with both a decline in the number of progeny and an increased incidence of defects. The cellular mechanisms of reproductive aging are not well understood, although a number of factors, both intrinsic and extrinsic to an organism's germline, may contribute to aging phenotypes. Recent work in a variety of organisms suggests that nuclear organization and nuclear envelope proteins may play a role in these processes.