Molecular insights into transgenerational non-genetic inheritance of acquired behaviours

Behavioural traits in mammals are influenced by environmental factors, which can interact with the genome and modulate its activity by complex molecular interplay. Environmental experiences can modify social, emotional and cognitive behaviours during an individual's lifetime, and result in acquired behavioural traits that can be transmitted to subsequent generations. This Review discusses the concept of, and experimental support for, non-genetic transgenerational inheritance of acquired traits involving the germ line in mammals. Possible mechanisms of induction and maintenance during development and adulthood are considered along with an interpretation of recent findings showing the involvement of epigenetic modifications and non-coding RNAs in male germ cells

The (not so) controversial role of DNA methylation in epigenetic inheritance across generations.

It has been demonstrated originally in plants that phenotypic traits, such as floral symmetry, can be caused by changes of methylation patterns of specific genes. Such traits can be transgenerationally inherited for multiple generations and remain associated with cytosine methylation patterns. Whether genomic methylation may also contribute to epigenetic inheritance across generations in vertebrates and notably in mammals is still more controversial. One reason for this tentativeness is the dual occurrence of global genomic de-methylation first in pre-implantation embryos and subsequently in primordial germ cells (PGCs) of mammals. Although gene focused cases of epigenetic inheritance associated with genomic DNA methylation have been well studied mostly in rodents (such as imprinted genes and the Agouti viable yellow, Avy, allele), it is still a matter of debate whether genomic DNA methylation may provide a more general mechanism for the epigenetic inheritance of acquired traits across generations. We review the current literature on this topic with a focus on the potential role of DNA methylation for epigenetic inheritance across generations in mammals