An investigation of factors influencing the survival of trisomic fetuses in the mouse.

The prevalence of trisomy at a given time of gestation depends on two factors: its incidence at conception and the probability that the trisomic embryo or fetus survives up to the time of observation. In mammals, little is known about the factors controlling either of these two events. A mouse model is particularly useful for these types of studies, as it allows us to examine each event, under strictly controlled experimental conditions. Using this mouse model, a systematic analysis of the influence of various factors including maternal age, diet, as well as fetal and maternal genes, on the survival of trisomic fetuses, at different times of gestation, has been performed. Our studies show that high post-implantation survival of trisomic fetuses is associated with a specific diet or a specific maternal gene, but not increasing maternal age. Future studies are aimed at identifying the specific genetic and environmental factors involved, and understanding their pathogenesis.