Dr. M: The first two thousand days for your new love, part 5
Epigenetics and pregnancy part III – Fathers
From the last two weeks discussion, we have concentrated on mothers and their offspring’s DNA being read or silenced by environmental inputs during pregnancy. What about dad’s? Do they matter?
Kinship theory is a principle of understanding that there is a battle going on between maternal genes and paternal genes and that they are represented in the child. Maternal genes are specially geared to making the mother and child well while preserving the mother’s reproductive capabilities. Paternal genes are geared toward enhancing the child’s utilization of the mother’s time and abilities.
Why would this be? According to Paul Raeburn’s book Do Fathers Matter, humans have imprinted genes that are unique to each sex and are set to promote their agenda. Male mammals notoriously reproduce with many mates to have a diverse and large offspring pool. Paternal imprinted genes promote growth in the offspring above all else. These genes send signals to the mother to give more time and resources to the child while the father moves on to reproduce again. While he is gone this imprinted plan will further his agenda of his gene’s proliferation.
Maternal imprinted genes have the opposite effect by slowing growth so as to preserve energy and resources for future offspring. As with everything in nature, there is a push-pull between mom and dad for the relative success of the offspring.
Let’s take this to a modern day issue of human mental health. Many imprinted genes are only functional in the brain while other≠s are found everywhere in the body. IGF2, insulin like growth factor, is a growth gene and is known to cause a disease called Beckwith Weidemann syndrome (BWS) if both paternal copies are turned on. The body overgrows as does the brain. These children also have a significant increased risk of autism and mental issues. Thus, we have a genetic risk for a disease based entirely on dad’s genes being activated at this locus. (J. Adams 2008) One epigenetic association trigger for BWS was found to be assisted reproductive technology. (M. DeBaun 2003)
There is evidence emerging that abnormal epigenetic changes to these paternally and maternally imprinted genes’ expression are the basis of some of our mental health concerns. Keeping these genes appropriately functioning will be our goal in the future. (A. Kalkbrenner 2014)
So, dad’s genes can play a significant role as well. Does dad’s fitness both mentally and physically matter?
Based on paternally derived genetic risk autism association data, there are studies showing that certain occupations and chemical exposure may increase an offspring’s autism risk. (A. Dickerson et. al. 2014)(K. Keil et. al. 2016)
“Two large, independent twin studies that examined the relative contributions of genetic heritability versus the shared environment similarly concluded that environmental factors were more predominant than genetic factors in determining autism risk. A significant role for environmental factors in determining ASD risk is consistent with the clinical heterogeneity that is a hallmark characteristic of these neurodevelopmental disorders and suggests a plausible explanation for the exponential rise in ASD cases over the past several decades.” (K. Keil et. al. 2016)
Dr. T. Desrosiers and her team evaluated the effects of chemical exposure in fathers at work and subsequent birth defects in offspring. They found positive correlations between paternal chemical exposure and birth defects. (T. Desrosiers et. al. 2012)
This data is only associative and not causative proof. However, the principle has to be that we men avoid all possible triggers for genetic mishaps by avoiding chemicals, eating well, reducing stress and being mentally balanced. These conserved principles are the root of every way to avoid disease or treat as far as I am concerned.
Clearly, fathers can have profound genetic effects on their offspring. There are a few hundred imprinted genes that a father provides that are critical to a child’s growth that a mother does not have.
While continuing my reading of Do Fathers Matter, I rediscovered a researcher that I admire. Michael Skinner has shown us a snapshot of the genetic effects of chemicals on parents and thus on their offspring through rat studies. They found that the genetic effects in the first generation are conserved in future generation’s genomes through epigenetic shifts, called transgenerational epigenetics. There are a myriad of potential triggers to these epigenetic shifts.
In Dr. Skinner’s work, he exposed rats to vinclozolin, a fungicide used on fruit and vegetable plants. Vinclozolin turned off some rat genes that were previously on and had the opposite effect on other genes. These abnormal gene changes were found in multiple generations of rat offspring. These studies are being reproduced and further studied to see how this data translates into humans.
A quick Google scholars search for paternal chemical exposure and birth defects returns over 30,000 articles. A quick perusal of many of these studies is disturbing.
The difficulty in translating these data sets into the human experience is that they are all risk associations and not de facto proof.
What we now know is that a father’s pre-conception activity affects the sperm and its DNA expression. Chemicals, diet, stress and drugs are the major players in these shifts and most men are oblivious to this fact.
We have long concentrated on maternal health as the only guide to a child’s genetic and infancy health. This data is telling us to concentrate on fathers and their health overall as well.
Next – What to do?
Dr. Chris Magryta is a physician at Salisbury Pediatric Associates. Contact him at email@example.com