Figure 1.

Intergenerational vs. transgenerational epigenetic inheritance. Epigenetic alterations can be induced by parental exposure to certain conditions such as lifestyle, including nutrition and exposure to different types of xenobiotics. Those changes, when present in germ cells and/or mature gametes (red stars) are transmitted to the offspring, in a phenomenon known as epigenetic inheritance. If the phenotype is observed further than the second or third generation (when the exposed progenitor is a gestating mother) a transgenerational epigenetic inheritance is observed (gray pentagons). If the phenotype is only observed in first generation (or second, for the exposure of a gestating mother), this is considered a parental effect and it is known as intergenerational epigenetic inheritance (black hexagons).