Human DNA has over 25,000 genes; each of the 23 pairs of human chromosomes encodes thousands of genes. Until recently it was believed that the genes you were born with determined the future status of your health. Now with the discovery of epigenetics, it is known that genes can get turned on and off. Our DNA is the code the body uses to build and regenerate itself. Genes however need instructions for what to do and when to do it.
The DNA in the nucleus is precisely wound, folded, and compacted into chromosomes so that it will fit into the nucleus. It is also organized so that specific segments can be accessed as needed by a specific cell type.
Epigenetics describes the physiological reprogramming that occurs in the cell without changes in the DNA sequence. The main epigenetic tools used by the cell are:
- DNA methylation
- Histone modifications
- Histone variants
- Chromatin remodeling
- Regulatory activity of microRNAs (miRNAs).
The combinative use of these tools regulates the accessibility of the DNA to outside factors in the nucleus, which affects vital cellular processes including transcription and DNA repair.
The epigenetic modifications are known as tags and they provide the instructions to the DNA. Several of these tags have been discovered, but the two main ones involve methyl groups (made of carbon and hydrogen) and histones (a type of protein). To imagine how tags work, think of a gene as a lamp. Methyl groups act as an on-off switch that turn a gene on or off. Histones, on the other hand, act like a dimmer switch, regulating gene activity up or down. It’s thought that we have four million of these switches that are triggered by lifestyle and environmental factors.
DNA modifications that do not change the DNA sequence can affect gene activity. Environmental influences, such as a person’s diet and exposure to pollutants, can also impact the epigenome. Epigenetic changes can help determine whether genes are turned on or off and can influence the production of proteins in certain cells, ensuring that only necessary proteins are produced. For example, proteins that promote bone growth are not produced in muscle cells. Patterns of epigenome modification vary among individuals, different tissues within an individual, and even different cells.
Our DNA is packaged by wrapping around histone proteins. Histone proteins act like a spool that DNA can be wound around to become more compact. Initially, 146 base-pairs of DNA are wrapped.Under the electron microscope, this winding of DNA around histone proteins looks like small beads on a string . These beads (histone proteins) can move along the string (DNA) and change the structure of the molecule. Histones package and order DNA into structural units called nucleosome complexes, which can control the access of proteins to the DNA regions. If DNA encoding a specific gene is to be transcribed into RNA, the nucleosomes surrounding that region of DNA can slide down the DNA to open that specific chromosomal region and allow for the transcriptional machinery (RNA polymerase) to initiate transcription . Nucleosomes can move to open the chromosome structure to expose a segment of DNA, but do so in a very controlled manner. Chemical modifications to either the histone proteins or the DNA itself signals whether or not a particular region of the genome should be “open” or “closed” to the transcription machinery.
Modifications such as acetylation or methylation of the histones can alter how tightly DNA is wrapped around them, while methylation of DNA changes how the DNA interacts with proteins, including the histone proteins that control access to the region. This type of genetic regulation is called epigenetic regulation as it does not change the nucleotide sequence of the DNA.
There are many factors that influence whether genes are turned on or off. One of these is an epigenetic process called methylation, in which a group of carbon and hydrogen atoms (a methyl group) attaches to DNA, adjusting how genes are expressed. When methyl groups are added to a particular gene, that gene is turned off or silenced, and no protein is produced from that gene.
Diet, Sleep And Exercise Modulate Gene Expression
One of the factors that modulates gene expression is diet. A diet high in refined carbohydrates that promotes high blood glucose attacks your DNA. On the other hand, compounds like sulforaphane (found in broccoli), curcumin (turmeric), epigallocatechin gallate (green tea), and resveratrol (wine) can slow or potentially reverse DNA damage.
Inadequate sleep also disrupts genetic activity. A team of researchers that included sleep science and genetics experts examined the influence of sleep on gene function and discovered that just a single week of insufficient sleep altered the activity of over 700 genes.
It’s well accepted that physical exercise is one of the best things you can do for your overall health and mental well-being. Now there’s evidence that physical exercise can positively affect gene expression.
So Do Stress, Relationships, And Thoughts
Not only do tangible factors like diet, sleep, and exercise affect your genes, so do intangibles like stress, your relationships with others, and your thoughts. One of the most powerful stress reduction techniques, mindfulness meditation, turns down the expression of pro-inflammatory genes thus reducing inflammation. This down regulation of inflammation occurred in as little as 8 hours of meditation.
Dr. Dawson Church is an award-winning author whose bestselling book, Genie in Your Genes: Epigenetic Medicine and the New Biology of Intention, has been hailed as a breakthrough in the field of epigenetics. In his book, Church cites over 400 scientific studies that show how intangibles like the expression of gratitude, acts of kindness, optimism, and mind-body healing techniques like the Emotional Freedom Technique positively affect the expression of genes. And just as in the meditation study, these epigenetic benefits were often experienced immediately.
It’s not only positive habits that affect your genes though. So do the bad ones. Substance abuse, addictions, inactivity, malnutrition, and exposure to toxins negatively affect the way your genes express themselves. Researchers have found that emotional factors such as trauma and stress can activate harmful epigenetic changes.
Epigenetics Changes Last For Generations
One of the most amazing and controversial discoveries is that epigenetic changes don’t stop with you. Epigenetic signals from the environment can be passed from one generation to the next, sometimes for several generations, without changing a single gene sequence.
Another way our genes are turned on or off are through gene transcription. During transcription, the first step in reading the gene’s directions and getting proteins made, the nucleus of the cell needs to figure out how to get its knowledge transferred. It does this by copying itself and sending the copy off to share the directions. This is like you copying out driving directions ahead of time and sharing them with everyone else.Of course, if you can’t get to those directions, you can’t share them, either. That is how gene regulation works during transcription. A protein, called the transcription factor, can either cover up the gene directions or reveal them, thus determining whether the gene is on or off.
Epigenetics is an exciting new discovery that allows hope for those who have genetics that they inhereted. The ability to switch on and off genes and to silence genes that can damage our health is an enormous breakthrough. The potential for health benefits as a result is limitless.
About the Author
Jacine Greenwood is an internationally recognised educator who is known within the industry for her up to date knowledge and her ability to deliver training in an easy to understand method.
Jacine holds 6 Diplomas and a Bachelor of Nursing and her knowledge is well respected by her peers. She is also a qualified Cosmetic Chemist. With over 19 years experience in the industry and a background of cosmetic formulation, Jacine has an immense knowledge of current trends in research and new developments in the industry.
Jacine has been continually educating herself in all aspects of skin function and cosmetic chemistry for the past 21 years. Jacine’s knowledge is current and has a vast knowledge of the active ingredients that are being released onto the market.
The American Society of Human Genetics. “Six Things Everyone Should Know About Genetics.” (July 26, 2010) http://www.ashg.org/education/everyone_1.shtml
Lobo, Ingrid, Ph.D. “Environmental Influences on Gene Expression.” Nature Education. 2008. (July 27, 2010) http://www.nature.com/scitable/topicpage/environmental-influences-on-gene-expression-536
National Center for Biotechnology Information. “Genes and Disease.” (July 26, 2010) http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gnd
The National Institute of Environmental Health Sciences. “Making it in a Tough Environment. You and Your Genes.” (July 29, 2010)http://www.niehs.nih.gov/health/scied/documents/You-YourGenes.pdf
National Institute of General Medical Sciences. “The New Genetics.” (July 27, 2010) http://publications.nigms.nih.gov/thenewgenetics/
Philipkoski, Kristen. “How to Turn On a Gene.” WIRED. Feb. 6, 2002. (July 27, 2010) http://www.wired.com/medtech/health/news/2002/02/50100/
Science. “Epigenetics: A Web Tour.” (Apr. 26, 2010) http://www.sciencemag.org/feature/plus/sfg/resources/res_epigenetics.dtl
Starr, Dr. Barry. “Ask a Geneticist.” The Tech Museum. (July 27, 2010) http://www.thetech.org/genetics/ask.php?id=63
The Tech Museum. “What is a Gene?” (July 26, 2010) http://www.thetech.org/genetics/feature.php
TeensHealth. “The Basics on Genes and Genetic Disorders.” April 2009. (July 26, 2010) http://kidshealth.org/teen/your_body/health_basics/genes_genetic_disorders.html
The University of Utah. “Proteins.” (Aug. 1, 2010)http://learn.genetics.utah.edu/content/begin/dna/
U.S. Department of Energy Genome Programs. “Genetic Disease Information — pronto!” July 21, 2008. (July 26, 2010) http://www.ornl.gov/sci/techresources/Human_Genome/medicine/assist.shtml
U.S. National Library of Medicine. “Handbook: Help Me Understand Genetics.” July 25, 2010. (July 26, 2010) http://ghr.nlm.nih.gov/handbook
Weinhold, Bob. “Epigenetics: The Science of Change.” Environmental Health Perspectives. March 1, 2006. (April 27, 2010)http://ehp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info:doi/10.1289/ehp.114-a160
World Health Organization. “Genes and human disease.” (July 26, 2010) http://www.who.int/genomics/public/geneticdiseases/en/