Figure 1.

Emerging concepts in environmental epigenetic regulation in asthma. Emerging concepts include assessing a greater understanding of the importance of individual versus mixtures and sequential environmental exposures, both toxic and protective; their time course may affect the timeline of epigenetic regulation. Although the perinatal time-window of susceptibility has emerged as key, others, such as adolescence and elderly periods, are under investigation. Studies may need to consider epigenetic patterns in the setting of divergence of whole populations over time, and examine the dynamics of the epigenetic responses, including over generations of individuals.