Two items before getting to the review:

• 94% of rodent genera are naturally uniparental;
• The Rattus and Mus genera used in almost all rodent research aren’t part of the 6% in which fathers also provide offspring care.

This 2018 Australian review subject was paternal intergenerational and transgenerational transmission of biological and behavioral phenotypes per this partial outline:

“Evidence for non-genetic inheritance of behavioral traits in human populations

• Intergenerational inheritance modulating offspring phenotypes following paternal exposure to trauma
• Epigenetic inheritance via the germline following paternal environmental exposures
• Limitations of research on epigenetic inheritance in human populations

The transgenerational impact of stressful paternal environments

• Impact of paternal stress on affective behaviors and HPA-axis regulation of progeny
• Influence of paternal stress exposure on offspring cognition
• Role of sperm-borne microRNAs in the epigenetic inheritance of stress

Sexually dimorphic aspects of paternal transgenerational epigenetic inheritance”

The review was comprehensive, and filled in the above outline with many details towards the goal of:

“This exciting new field of transgenerational epigenomics will facilitate the development of novel strategies to predict, prevent and treat negative epigenetic consequences on offspring health, and psychiatric disorders in particular.”

The reviewers also demonstrated that current intergenerational and transgenerational research paradigms exclude a father’s child care behavior.

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The fact that studies use rat and mouse species where fathers don’t naturally provide care for their offspring has warped the translation of findings to humans. The underlying question every animal study must answer is: how can its information be used to help humans? I asked in A limited study of parental transmission of anxiety/stress-reactive traits:

“How did parental behavioral transmission of behavioral traits and epigenetic changes become a subject not worth investigating? These traits and effects can be seen everyday in real-life human interactions, and in every human’s physiology.”

Who among us doesn’t still have biological and behavioral consequences from our experiences of our father’s child care actions and inactions? Why can’t researchers and sponsors investigate these back to their sources that may include grandparents and great-grandparents?

Such efforts weren’t apparent in the review’s 116 cited references that included:

• Transgenerational epigenetic programming with stress and microRNA
• A cited study in What is epigenetic inheritance?

The reviewer in the latter has been instrumental in excluding behavioral inheritance mechanisms from these research paradigms, leading to my questions:

1. “If the experimental subjects had no more control over their behavioral stress-response effects than they had over their DNA methylation, histone modification, or microRNA stress-response effects, then why was such behavior not included in the “epigenetic mechanisms” term?
2. How do behavioral inheritance mechanisms fall outside the “true epigenetic inheritance” term when behavioral stress-response effects are shown to be reliably transmitted generation after generation?
3. Wouldn’t the cessation of behavioral inheritance mechanisms confirm their status by falsifiability as was similarly done with studies such as the 1995 Adoption reverses the long-term impairment in glucocorticoid feedback induced by prenatal stress?”

Translating rodent studies into human mothers’ behavioral transmission of biological and behavioral phenotypes isn’t hampered by the studied species’ traits as it is for human fathers. But sponsors have to have the guts to support human research that may not produce politically-correct findings.

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http://www.translatingtime.org provides an inter-species comparative timeline. For example, an input of:

• Species 1: Human
• Process: Lifespan
• Location: Whole Organism
• Days (post-conception): 270
• Species 2: Mouse

produces a list of event predictions. Note how many significant events occur before humans are born at day 270, assuming everything goes right with our developmental processes! Also, the model predictions for humans end at post-conception day 979, three weeks short of when we celebrate our second birthday.

https://www.nature.com/articles/s41380-018-0039-z “Transgenerational epigenetic influences of paternal environmental exposures on brain function and predisposition to psychiatric disorders” (not freely available) Thanks to Dr. Shlomo Yeshurun for providing a full copy.