Introduction

For a long time, the science of genetics showed that acquired characteristics don’t change the DNA sequence and therefore can’t be passed on to the offspring. However, in recent years it is becoming evident that this isn’t true. For example, in a study scientists suggested that a parental high‐fat diet before the intrauterine developmental stage may increase body‐fat accumulation in the offspring.  This suggests the possibility that parental diet may influence the lifelong health of offspring and epigenetic inheritance may occur (Wu & Suzuki, 2006). Living conditions such as stress could also affect the offspring. Studies showed that distinct prenatal adversities predict decreased DNA methylation in a gene that is relevant for childbirth, maternal behaviour and the wellbeing of mother and offspring (Unternaehrer et al., 2016). Scientists call this phenomenon epigenetic inheritance. Certain modifications of DNA affect how genes are read.

A better learning ability was inherited

Physical and mental activity isn’t only good for your own brain. New studies suggest that these activities can influence the learning ability of offspring. They showed that exposure of adult male mice to an environmental enrichment paradigm leads to enhancement of synaptic plasticity and cognition also in the next generation. This form of epigenetic inheritance is mediated by certain RNA molecules. This RNA molecules influence the gene activity and accumulate after physical and mental activity in the brain and also in the germ cells (Benito et al., 2017)

In their experiment, they exposed mice to an environment in which they had a lot of exercises. Also, it is known that mental and physical activity improve cognitive abilities and reduce the risk of diseases such as Alzheimer (Scarmeas et al., 2009). How would this affect the later mouse offspring? In fact, the rodents apparently benefited from the stimulating living conditions in which their parents had lived. For example, they performed better in learning ability tests compared to offspring from a control group.

Synaptic plasticity was improved

Synaptic plasticity is the ability of nerve cells to adapt flexibly to new requirements and communicate well with one another. This is the basic foundation for learning. In this study, they demonstrated that exposure of adult mice to environmental enrichment significantly enhances hippocampal Long-Term-Potential and cognitive function in their offspring. Notably, offspring of fathers that had more activity had increased LTP compared to those born to fathers that were not active.

RNA influences gene activity

In their experiment, they extracted RNA from the sperm of the tested mice that were physically and mentally active. These were injected into fertilized eggs and examined the animals that developed from them. Further investigations revealed which RNAs were responsible for epigenetic inheritance. Thus, two so-called microRNAs – miRNA212 and miRNA132 – could explain the inherited learning ability.

These control molecules influence the activation of genes. In addition, they found that miRNA212 and miRNA132 accumulate in the brain and spermatozoa after physical and mental activity.

In humans, physical activity and mental training increase the ability to learn (Driskell et al., 1994; Fabre et al., 2002). It’s not easy to study whether our learning ability is epigenetically inherited or not in humans. However, these studies help us to have a better understanding of how physical and mental activity could influence our offsprings.

COPYRIGHT: This article is the property of We Speak Science, a non-profit institution co-founded by Dr. Detina Zalli (Harvard University) and Dr. Argita Zalli (Imperial College London). The article is written by Dardan Beqaj, M.Sc. Microbiology, Eberhard-Karls University of Tübingen).

REFERENCES:

Benito, Eva, et al. “RNA-dependent intergenerational inheritance of enhanced synaptic plasticity after environmental enrichment.” bioRxiv (2017): 178814.

Wu, Q., and M. Suzuki. “Parental obesity and overweight affect the body‐fat accumulation in the offspring: the possible effect of a high‐fat diet through epigenetic inheritance.” Obesity reviews 7.2 (2006): 201-208.

Huypens, Peter, et al. “Epigenetic germline inheritance of diet-induced obesity and insulin resistance.” Nature genetics 48.5 (2016): 497.

Unternaehrer, Eva, et al. “Maternal adversities during pregnancy and cord blood oxytocin receptor (OXTR) DNA methylation.” Social cognitive and affective neuroscience 11.9 (2016): 1460-1470.

Scarmeas, Nikolaos, et al. “Physical activity, diet, and risk of Alzheimer disease.” Jama 302.6 (2009): 627-637.

Driskell, James E., Carolyn Copper, and Aidan Moran. “Does mental practice enhance performance?.” Journal of applied psychology 79.4 (1994): 481.

Fabre, C., et al. “Improvement of cognitive function by mental and/or individualized aerobic training in healthy elderly subjects.” International journal of sports medicine 23.06 (2002): 415-421.