Figure 1.

Intergenerational and transgenerational transmission. The nicotine-exposed founder male is bred with drug naïve female to produce the F1 generation. Changes in the F1 phenotype represent intergenerational transmission of nicotine’s effects from the founder to his offspring. The F1 males and females derived from the nicotine exposed founder male are bred with drug naïve females and males to produce the F2 generation. Changes in F2 phenotype represent transgenerational transmission of nicotine’s effects in the founder via F1 to the F2 generation. The intergenerational transmission is believed to occur due to epigenetic changes in the founder’s germline produced by the direct effects of nicotine. This paradigm permits analysis of the effects of nicotine on somatic and germ cells in the founder male as well as in males and females in multiple generations of descendants.