Epigenetic Memories are Passed Down 14 Successive GenerationsPosted on: Saturday, October 13th 2018 at 5:30 amWritten By:GreenMedInfo Research Group
The past of our ancestors lives on through us: Groundbreaking research illustrates how parental experience is not only epigenetically imprinted onto offspring, but onto an unprecedented number of future generations. Rather than occurring over the elongated time scale of millions of years, genetic change can transpire in real biological time through nanoparticles known as exosomes.
Until recently, it was believed that our genes dictate our destiny. That we are slated for the diseases that will ultimately beset us based upon the pre-wired indecipherable code written in stone in our genetic material. The burgeoning field of epigenetics, however, is overturning these tenets, and ushering in a school of thought where nurture, not nature, is seen to be the predominant influence when it comes to genetic expression and our freedom from or affliction by chronic disease.
Epigenetics: The Demise of Biological Determinism
Epigenetics, or the study of the physiological mechanisms that silence or activate genes, encompasses processes which alter gene function without changing the sequence of nucleotide base pairs in our DNA. Translated literally to mean “in addition to changes in genetic sequence,” epigenetics includes processes such as methylation, acetylation, phosphorylation, sumolyation, and ubiquitylation which can be transmitted to daughter cells upon cell division (1). Methylation, for example, is the attachment of simple methyl group tags to DNA molecules, which can repress transcription of a gene when it occurs in the region of a gene promoter. This simple methyl group, or a carbon bound to three hydrogen molecules, effectively turns the gene off.
Post-translational modifications of histone proteins is another epigenetic process. Histones help to package and condense the DNA double helix into the cell nucleus in a complex called chromatin, which can be modified by enzymes, acetyl groups, and forms of RNA called small interfering RNAs and microRNAs (1). These chemical modifications of chromatin influence its three-dimensional structure, which in turn governs its accessibility for DNA transcription and dictates whether genes are expressed or not.
We inherit one allele, or variant, of each gene from our mother and the other from our father. If the result of epigenetic processes is imprinting, a phenomenon where one of the two alleles of a gene pair is turned off, this can generate a deleterious health outcome if the expressed allele is defective or increases our susceptibility to infections or toxicants (1). Studies link cancers of nearly all types, neurobehavioral and cognitive dysfunction, respiratory illnesses, autoimmune disorders, reproductive anomalies, and cardiovascular disease to epigenetic mechanisms (1). For example, the cardiac antiarrhythmic drug procainamide and the antihypertensive agent hydralazine can cause lupus in some people by causing aberrant patterns of DNA methylation and disrupting signaling pathways (1).
Genes Load the Gun, Environment Pulls the Trigger
Pharmaceuticals, however, are not the only agents that can induce epigenetic disturbances. Whether you were born via vaginal birth or Cesarean section, breastfed or bottle-fed, raised with a pet in the house, or infected with certain childhood illnesses all influence your epigenetic expression. Whether you are sedentary, pray, smoke, mediate, do yoga, have an extensive network of social support or are alienated from your community—all of your lifestyle choices play into your risk for disease operating through mechanisms of epigenetics.
In fact, the Centers for Disease Control (CDC) states that genetics account for only 10% of disease, with the remaining 90% owing to environmental variables (2). An article published in the Public Library of Science One (PLoS One) entitled “Genetic factors are not the major causes of chronic diseases” echoes these claims, citing that chronic disease is only 16.4% genetic, and 84.6% environmental (3). These concepts make sense in light of research on the exposome, the cumulative measure of all the environmental insults an individual incurs during their life course that determines susceptibility to disease (4).
In delineating the totality of exposures to which an individual is subjected over their lifetime, the exposome can be subdivided into three overlapping and intertwined domains. One segment of the exposome called the internal environment is comprised of processes innate to the body which impinge on the cellular milieu. This encompasses hormones and other cellular messengers, oxidative stress, inflammation, lipid peroxidation, bodily morphology, the gut microbiota, aging and biochemical stress (5).
Another portion of the exposome, the specific external environment, consists of exposures including pathogens, radiation, chemical contaminants and pollutants, and medical interventions, as well as dietary, lifestyle, and occupational elements (5). At an even broader sociocultural and ecological level is the segment of the exposome called the general external environment, which may circumscribe factors such as psychological stress, socioeconomic status, geopolitical variables, educational attainment, urban or rural residence, and climate (5).
Transgenerational Inheritance of Epigenetic Change: Endocrine Disruptors Trigger Infertility in Future Generations …
There is no more pivotal time for imposing vandalized imprinted epigenetics than birth. And the birth imprint has been delegated to our medical authority figures, who don’t know what they’re talking about and most of whom apparently don’t care. Which is largely why this country is on the brink of catastrophe.
A tiny bit of humility would be in order here. But I’m not holding my breath.