The Logic of Transgenerational Inheritance: Timescales of Adaptation

Myriad mechanisms have evolved to adapt to changing environments. Environmental stimuli alter organisms' physiology to create memories of previous environments. Whether these environmental memories can cross the generational barrier has interested scientists for centuries. The logic of passing on information from generation to generation is not well understood. When is it useful to remember ancestral conditions, and when might it be deleterious to continue to respond to a context that may no longer exist? The key might be found in understanding the environmental conditions that trigger long-lasting adaptive responses. We discuss the logic that biological systems may use to remember environmental conditions. Responses spanning different generational timescales employ different molecular machineries and may result from differences in the duration or intensity of the exposure. Understanding the molecular components of multigenerational inheritance and the logic underlying beneficial and maladaptive adaptations is fundamental to understanding how organisms acquire and transmit environmental memories across generations.