By Don MacGillivray

 

Portland is increasingly interested in addressing issues about equity of opportunity. In a society with wide economic diversity, opportunities are not distributed equally.

Much of the responsibility for taking advantage of opportunity is up to the individual, but science is learning more about how to  make changes that improve the lives of many people, if not everyone. The research being done on epigenetics (the study of heritable changes that happen but not in a DNA sequence) is an area that holds great potential.

Discoveries in epigenetics are rewriting the rules of disease, heredity and identity. An even greater surprise is the recent discovery that epigenetic signals can be passed on from one generation to the next, sometimes for several generations, without changing a single gene sequence.

A growing body of evidence suggests that epigenetic changes influenced by one’s diet, behavior, or surroundings can work their way into the genes and echo far into the future.

In recent years, researchers have made great strides in understanding the molecular sequences and patterns that determine which genes can be turned on or off. More and more researchers are finding that an extra bit of a vitamin, a brief exposure to a toxin, even an added dose of mothering can tweak the epigenome and thereby alter the software of our genes in ways that affect an individual’s body and brain for life.

The 25,000 genes identified in our DNA by the Human Genome Project are now regarded as the instruction book for the human body, but genes themselves need instructions to know what to do and where and when to do it.

A human liver cell contains the same DNA as a brain cell, yet somehow it knows to code only those proteins needed for the functioning of the liver. Those instructions are found in an array of chemical markers and switches known collectively as the epigenome.

Simply put, epigenetics is a process that happens throughout our lives and is normal to development. It is possible that our environment, from smoking and diet to pollution and war can leave epigenetic marks on our DNA. Unlike genetic mutations, epigenetic changes are potentially reversible and defective genes might be encouraged to create a healthy pattern and continue to function.

Towards the end of the Second World War, Europe experienced a famine. Because of the collusion of the Dutch with the Allies’ in 1944, the Nazis blockaded towns across the western Netherlands for more than six months.

The resultant food shortages were severe with just 580 calories of food per person per day. Over 22,000 people died from malnutrition.

Thorough analysis of the Dutch medical records decades later showed that the health effects of surviving infants with prenatal exposure to famine were more susceptible to health problems. They also found that the children of these children, born years later, and well-fed, were also significantly underweight.

Abnormal patterns have been found in many cancers including cancer of the colon, stomach, cervix, prostate, thyroid, and breast. Once we understand the connection between our epigenome and diseases like cancer, lifelong diet changes may be the way to stay healthy.

At a major university, a study suggests that soaring obesity and autism rates in humans could be due to the chemical revolution of the Forties and our grandparents’ exposure to plastics, fertilizers and detergents as if the exposure three generations before has reprogrammed the brain.

Socioeconomic factors like poverty might affect the genes of children and leave them more prone to drug addiction and depression in later life.

Only 50 percent of the DNA we inherit from our parents are chromosomes. The other 50 percent is made up of proteins that carry epigenetic markers. The markers are different in every type of human tissue type and change over time.

Many scientists remained skeptical because the mechanism by which such inheritance works is still a mystery. Researchers still don’t understand the scientific mechanism of how it happens. Explaining it requires looking into reproductive biology to find out how the signals might be formed. Thousands of different factors could explain health patterns in the generations of the same family.

In the space of two decades, the field of epigenetics has exploded. New research claims environmental factors affect not just an individual’s genes, but the genes of their offspring too, and that nurture, rather than nature may determine who we are far more than what was previously thought.

Now everything we do, everything we eat, drink or smoke can affect our genes and those of future generations. Some day with more work perhaps we’ll have more control over our genetic legacy.

Many children live in poverty and suffer from the problems of abuse, neglect, uncertainty about food and housing. Childhood trauma, often called “toxic stress” influences future brain development and future medical health.

Exposure to high degrees of adversity can dramatically affect the brain structure and function. The earlier there is intervention the greater the opportunities and success in the future. Epigenetic solutions may hold an answer to some of these challenges.