Genetics and the Life Course

A life-course perspective is committed to the proposition that from conception to death, all human outcomes are the result of a continual interaction between the individual and all of the environments that he or she inhabits at any given point in time. Early development is a critical period, a window of time during the life course when a given exposure can have a critical or permanent influence on later outcomes. But the impact of exposures upon outcomes does not end at any specific point in time, inasmuch as life is a continuing interactive and adaptive process. We now know that what applies to human beings also applies to their genomes. The “outcome” of any gene at any given point in time (whether or not it is used to transcribe a particular protein, what form of that protein, and how much) is a product of the interaction between the gene and the multiple environments of which it is a part, which include the epigenome, the cell, the biological human, and the assorted environments he or she occupies (e.g., geographical, socioeconomic, ethnic, etc.). Early life experiences can permanently “reprogram” the epigenome and gene transcription with life-long behavioral consequences. At the same time, the epigenome as well as the genome continue to be environmentally responsive throughout the life course.