Heritable consequences of paternal nicotine exposure: from phenomena to mechanisms

Our understanding of the interactions between genetic and environmental factors in shaping behavioral phenotypes has expanded to include environment-induced epigenetic modifications and the intriguing possibility of their association with heritable behavioral phenotypes. The molecular basis of heritability of phenotypes arising from environment-induced epigenetic modifications is not well defined yet. However, phenomenological evidence in favor of it is accumulating rapidly. The resurgence of interest has led to focus on epigenetic modification of germ cells as a plausible mechanism of heritability. Perhaps partly because of practical reasons such as ease of access to male germ cells compared to female germ cells, attention has turned toward heritable effects of environmental influences on male founders. Public health implications of heritable effects of paternal exposures to addictive substances or to psycho-social factors may be enormous. Considering nicotine alone, over a billion people worldwide use nicotine-containing products, and the majority are men. Historically, the adverse effects of nicotine use by pregnant women received much attention by scientists and public policy experts alike. The implications of nicotine use by men for the physical and mental well-being of their children were not at the forefront of research until recently. Here, we review progress in the emerging field of heritable effects of paternal nicotine exposure and its implications for behavioral health of individuals in multiple generations. [GRAPHICS] .

Automated summary

Research has expanded our understanding of how genetic and environmental factors interact to shape behavioral phenotypes, including environment-induced epigenetic modifications and their potential association with heritable behavioral phenotypes. The molecular basis of phenotypes resulting from environment-induced epigenetic modifications is not well defined, but there is accumulating phenomenological evidence in support of it. Attention has turned to epigenetic modification of germ cells as a possible mechanism of heritability, particularly focusing on the heritable effects of environmental influences on male founders.