Box: Outstanding questions

• What is the relative contribution of the epigenetic inheritance in comparison with the genetic one?

• Is transgenerational epigenetic inheritance widespread across species?

• How is phenotypic information originating in somatic tissues transmitted to germ cells?

• How many generations can epigenetic memory persist?

• Why do non-genomic effects disappear over a few generations?

• Could transgenerational epigenetic processes influence genetic inheritance, and vice versa?

• Are mechanisms responsible for transgenerational non-genomic effects the same across species?