Towards a new developmental synthesis: adaptive developmental plasticity and human disease

Consideration of the outcomes of developmental plasticity acting over the intermediate timescale is now important.20 Developmental plasticity evolved because it is adaptive, promoting Darwinian fitness by enhancement of survival and reproductive success.21 Plasticity uses environmental cues (which in mammals are transduced and buffered by the mother) to optimise the life-course strategy for maximum fitness, both making the best of present conditions and being well prepared for the future environment.22 Hormones and nutrients that cross the placenta can be affected by the mother's body composition, metabolism, and long-term lifestyle and by her immediate diet and stress levels. [...] environmental cues affecting development provide historical information that offspring use to predict the future.23 However, this anticipatory strategy has limitations, especially for long-lived species such as human beings, with the result that challenges during development can induce responses that have short-term benefits for the mother or the fetus but then longer term costs in terms of reduced fitness.24,25 When environmental conditions change strikingly between conception and adulthood, as has happened in most current human populations, the potential for a substantial mismatch is especially great, and this difference contributes to disease risk.