The great battle between nature and nurture continues. Social scientists, biologists, neurologists, psychiatrists, even theologians have debated for centuries what determines a person’s unique humanness. The field of genetics fired a seemingly victorious salvo against nurture as science discovered sections of DNA called “genes” which decided hair color, eye color, height, and even the presence of many diseases. The war was not settled there however. Everyone agreed that it did not seem to be that simple although many on the “nature” side kept searching for that next gene which would determine a person’s personality or which disease they would have. Some social scientists hung their hat on behaviorism and determinism, arguing that a person’s personality was a direct result of complex contributions from life. In their minds, the “person” was not left with much choice in who they were.
Will the battle ever be decided? What does “Epigenetics” have to say? Well, I like the statement by an honest psychiatric researcher I recently heard quoted. More or less, he recognized that a person develops out of “infinity squared”. A seemingly infinite number of “nature” factors (genes, physiology, and more) interacts with a seemingly infinite number of “nurture” factors (environmental, relationships, etc.) to produce your personality. The only thing “missing” is what the speaker who shared the quote had to add, “infinity times infinity times infinity”. The one who I was listening to added the spiritual dimension of life as another factor which included God’s work in us and our response to that work. No single factor determines who we are. We are infinitely complex as well as wonderfully made.
Epigenetics, in a sense, spans the nature / nurture divide and combines them into a single field of influences on a person’s life. Put another way, both what happens to you AND what you choose to do affects your health. Starting with classical genetics, you are given an “instruction book” of genes, half of the pages are from your Mom and half are from your Dad. The pages are paired so that you have two pages of each gene, one from your Mom and one from your Dad. Each cell in your body has the same “instruction book” of genes. No pages are missing in any cell, yet obviously blood cells are very different from skin cells. Different cells become different parts of your body by folding some pages down and bookmarking others. For example, blood cells don’t need to read all the genes for bone cells turned on by a bookmark. Eye cells don’t need to read all the genes for toenail cells.
Initially, this may seem all in favor of nature, reflecting another natural process which we don’t possess any control over. True, we don’t determine which cell becomes which body part, but much more lies under the “epigenetics umbrella” than is explained by classical genetics. Our environment, the “nurture”, affects how some of these genes are turned on or off by this page folding process. For example, children are affected by their environment in profound ways from the moment of conception (even before as we will later see). A pregnant mother’s smoking changes the baby’s brain and body. A pregnant mother’s nutrition or lack thereof affects the baby’s ability to develop normally. After birth, the lack of iron in the baby’s diet affects their brain in lasting ways. We suspect that viral infections may contribute to type I diabetes. This list could continue for pages and pages. Many of these effects are worked out through epigenetics through which genes are either folded down in the instruction book (and not read as often, or at all) or bookmarked to be read more often. Nurture makes a stunning comeback.
Epigenetics is not yet finished though. Our choices have a word to say in the matter. We are not chained to either our genes or our environment. Choices that we make as an individual for ourselves or for our children can also change which pages are folded and which are bookmarked in our genes. Our choices in regards to whether we expose ourselves to various environmental toxins can change which genes are expressed (used to make proteins in our bodies). Our choices of nutrition make a difference in how well the pages are turned down or bookmarked. If not adequately “folded” our cells may read pages that should not be read. If not adequately “bookmarked”, our cells may not read them enough. Furthermore, our nutrition also affects our body’s processing of various chemicals in our body. Too much or too little of these chemicals (like hormones and brain transmitters) affect our mood and ability to handle stress in signficant ways. You could say – self nurture affects us through choices in lifestyle.
Exercise has been shown to affect our genes in similar and other important ways. For example, the ends of our chromosomes (our DNA genes are connected in 46 total chromosomes in each cell), called telomeres, determine how long our body tissues can last. Longer telomeres means our cells can divide more times and our body can live longer. Exercise in childhood can keep our telomeres longer and likely cause us to live longer. So, our choices take the genes we have been given by God through our parents and produce our uniqueness for better or for worse.
In order to bring in the final “infinity factor”, the spiritual,, consider our emotions. Our emotions produce chemical changes in our body. Hormones change. The functioning of our body changes. Our epigenetic folded pages change. For example, studies have shown that babies who were born to mother’s carrying them during the 9/11 attacks have been changed for life. If mothers’ were pregnant in their third trimester, the babies have different hormonal responses to stress later in life. Also worth noting is that the hormones produced by stress can affect the processes which bookmark the epigenetic pages as well as change the way our brains process future stress. The final “infinity factor” of our spiritual nature affects how our emotions respond to these stresses and modifies our hormonal response. Two people can go through the same crisis and come out totally different based on what they believe.
Epigenetics brings “nature” and “nurture” together while placing a responsibility upon us to steward the genetics and epigenetics that God has given us. Romans tells us that God has placed us on this earth in the time and place He chose. We are elsewhere told that God gives different gifts and talents to different people (I Corinthians 12). Throughout the Bible we are commanded to not be afraid, to have faith, to walk in the Spirit, and more. We are to be stewards (implying responsibility) of the gifts God has given. This means cooperating with God, in the strength he provides (Philippians 4:13), in folding down the right pages. We are not locked in by our genetic code nor are we hemmed in by our environment. God, in His Word and through appropriate care of our bodies (God’s temple), has provided a means for a measure of healing (both physically and spiritually) on this earth – even if there may be scars which remain.