We can control some environmental factors—like diet, sun exposure, and exercise—through our behaviors. But as with our genes, there are plenty of environmental factors that we can’t change.
The place where we live brings many environmental factors along with it. The type of climate a place has, and whether it’s rural, urban, or something in between influence our traits. Factors like allergens, air quality, and water quality have powerful influences. Where a person lives also influences their access to food, recreational resources, transportation, social support, work and school environments, and medical care.
Sometimes even a temporary environmental factor can have a long-lasting effect on traits. Early social experiences shape our personalities. Brief exposure to a toxins or disease can have life-long effects. Being temporarily diagnosed with high blood pressure could lead to behavior changes. Even environmental factors from before birth can change traits in the long-term. For example, nutritional deficiencies or cigarette smoking during pregnancy can lead to a child with cleft palate.
In the end, it’s a mix of things we can and can’t control that determines our traits. As one example, we can’t control the risk for heart disease that comes from genes, nor environmental factors like age and gender. But these factors don’t determine our destiny. Our behaviors play a large part as well: the foods we eat, physical activities we pursue, and decisions about smoking all shape our risk of getting sick.
Many environmental factors are different between rural and urban settings.
Gene–environment interaction. Gene–environment interactions are the situation where the impact of an environmental exposure on disease risk is different for people with different genotypes, or conversely, situations where the impact of a genotype on disease risk is different in people with different environmental exposures. Studies of gene–environment interactions can provide insights into biological mechanisms of disease and could have public health implications. One example of a gene–environment interaction involves the NAT2 gene, smoking as the environmental factor, and bladder cancer. Tobacco smoking is a known risk factor for bladder cancer. According to the American Cancer Society, smokers are at least three times as likely to get bladder cancer as non-smokers. Smokers with one variant in NAT2 have a much higher risk of bladder cancer compared to smokers with a different variant. In other words,it's the combination, or interaction, of the genetic factor — NAT2 variation — and the environmental factor — smoking behavior — that determines the disease, bladder cancer risk.
Infographics
Epigenetics and Child Development: How Children’s Experiences Affect Their Genes
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For more information about epigenetics, please scroll down below the infographic.
New scientific research shows that environmental influences can actually affect whether and how genes are expressed. In fact, scientists have discovered that early experiences can determine how genes are turned on and off and even whether some are expressed at all. Thus, the old ideas that genes are “set in stone” or that they alone determine development have been disproven. Nature vs. Nurture is no longer a debate—it’s nearly always both!
More Information on Epigenetics
Deep Dive: Gene-Environment Interaction
Learn more about the physical and chemical processes that take place as part of the creation of the epigenome.Working Paper 10: Early Experiences Can Alter Gene Expression and Affect Long-Term Development
This in-depth working paper explains how genes and the environment interact, and gives recommendations for ways that caregivers and policymakers can effectively respond to the science.
During development, the DNA that makes up our genes accumulates chemical marks that determine how much or little of the genes is expressed. This collection of chemical marks is known as the “epigenome.” The different experiences children have rearrange those chemical marks. This explains why genetically identical twins can exhibit different behaviors, skills, health, and achievement.
Correcting Popular Misrepresentations of Science
Until recently, the influences of genes were thought to be set, and the effects of children’s experiences and environments on brain architecture and long-term physical and mental health outcomes remained a mystery. That lack of understanding led to several misleading conclusions about the degree to which negative and positive environmental factors and experiences can affect the developing fetus and young child. The following misconceptions are particularly important to set straight.
- Contrary to popular belief, the genes
inherited from one’s parents do not set a child’s future development in stone.
Variations in DNA sequences between individuals certainly influence the way in which genes are expressed and how the proteins encoded by those genes will function. But that is only part of the story—the environment in which one develops, before and soon after birth, provides powerful experiences that chemically modify certain genes which, in turn, define how much and when they are expressed. Thus, while genetic factors exert potent influences, environmental factors have the ability to alter the genes that were inherited. - Although frequently misunderstood, adverse fetal and early childhood experiences can—and do—lead to physical and chemical changes in the brain that can last a lifetime.
Injurious experiences, such as malnutrition, exposure to chemical toxins or drugs, and toxic stress before birth or in early childhood are not “forgotten,” but rather are built into the architecture of the developing brain through the epigenome. The “biological memories” associated with these epigenetic changes can affect multiple organ systems and increase the risk not only for poor physical and mental health outcomes but also for impairments in future learning capacity and behavior. - Despite some marketing claims to the contrary, the ability of so-called enrichment programs to enhance otherwise healthy brain development is not known.
While parents and policymakers might hope that playing Mozart recordings to newborns will produce epigenetic changes that enhance cognitive development, there is absolutely no scientific evidence that such exposure will shape the epigenome or enhance brain function. What research has shown is that specific epigenetic modifications do occur in brain cells as cognitive skills like learning and memory develop, and that repeated activation of brain circuits dedicated to learning and memory through interaction with the environment, such as reciprocal “serve and return” interaction with adults, facilitates these positive epigenetic modifications. We also know that sound maternal and fetal nutrition, combined with positive social-emotional support of children through their family and community environments, will reduce the likelihood of negative epigenetic modifications that increase the risk of later physical and mental health impairments.
The epigenome can be affected by positive experiences, such as supportive relationships and opportunities for learning, or negative influences, such as environmental toxins or stressful life circumstances, which leave a unique epigenetic “signature” on the genes. These signatures can be temporary or permanent and both types affect how easily the genes are switched on or off. Recent research demonstrates that there may be ways to reverse certain negative changes and restore healthy functioning, but that takes a lot more effort, may not be successful at changing all aspects of the signatures, and is costly. Thus, the very best strategy is to support responsive relationships and reduce stress to build strong brains from the beginning, helping children grow up to be healthy, productive members of society.
For more information: Early Experiences Can Alter Gene Expression and Affect Long-Term Development: Working Paper No. 10.
Full Text of the Graphic
“Epigenetics” is an emerging area of scientific research that shows how environmental influences—children’s experiences—actually affect the expression of their genes.
This means the old idea that genes are “set in stone” has been disproven. Nature vs. Nurture is no longer a debate. It’s nearly always both!
During development, the DNA that makes up our genes accumulates chemical marks that determine how much or little of the genes is expressed. This collection of chemical marks is known as the “epigenome.” The different experiences children have rearrange those chemical marks. This explains why genetically identical twins can exhibit different behaviors, skills, health, and achievement.
Epigenetics explains how early experiences can have lifelong impacts.
The genes children inherit from their biological parents provide information that guides their development. For example, how tall they could eventually become or the kind of temperament they could have.
When experiences during development rearrange the epigenetic marks that govern gene expression, they can change whether and how genes release the information they carry.
Thus,
the epigenome can be affected by positive experiences, such as supportive relationships and opportunities for learning, or negative influences, such as environmental toxins or
stressful life circumstances, which leave a unique epigenetic “signature” on the genes. These signatures can be temporary or permanent and both types affect how easily the genes are switched on or off. Recent research demonstrates that there may be ways to reverse certain negative changes and restore healthy
functioning. But the very best strategy is to support responsive relationships and reduce stress to build strong brains from the beginning.
Young brains are particularly sensitive to epigenetic changes.
Experiences very early in life, when the brain is developing most rapidly, cause epigenetic adaptations that influence whether, when, and how genes release their instructions for building future capacity for health, skills, and resilience. That’s why it’s crucial to provide supportive and nurturing experiences for young children in the earliest years.
Services such as high-quality health care for all pregnant women, infants, and toddlers, as well as support for new parents and caregivers can—quite literally— affect the chemistry around children’s genes. Supportive relationships and rich learning experiences generate positive epigenetic signatures that activate genetic potential.