There are many ways to mentally or even physically inherit traits from parents besides through genes, states a paper in Neuropsychopharmacology Reviews. And those other types of mechanisms, argues Cornell University pharmacologist Miklos Toth, are particularly important in trying to understand the heritability and genesis of psychiatric disorders.
“Inheritance is typically associated with the Mendelian transmission of information from parents to offspring by alleles (DNA sequence),” writes Toth. “However, empirical data clearly suggest that traits can be acquired from ancestors by mechanisms that do not involve genetic alleles, referred to as non-genetic inheritance.”
Toth points to “parental experience and exposure to certain environments, but also parental mutations and polymorphisms, because they can change the parental ‘intrinsic’ environment.” Toth states that studies of non-genetic inheritance have shown its importance in overall development, cardiovascular risk and metabolic symptoms.
“Multigenerational non-genetic inheritance is often interpreted as the transmission of epigenetic marks, such as DNA methylation and chromatin modifications, via the gametes (transgenerational epigenetic inheritance),” explains Toth. “However, information can be carried across generations by a large number of bioactive substances, including hormones, cytokines, and even microorganisms, without the involvement of the gametes. We reason that this broader definition of non-genetic inheritance is more appropriate, especially in the context of psychiatric disorders, because of the well-recognized role of parental and early life environmental factors in later life psychopathology.”
(Abstract) Mechanisms of Non-Genetic Inheritance and Psychiatric Disorders (Toth, Miklos. Neuropsychopharmacology Reviews. (2015) doi:10.1038/npp.2014.127.)