Genetic Health Changes

Every human being is made up of trillions of cells. A cell’s nucleus accommodates chromosomes, which are made up of a nucleic acid called DNA. Segments of DNA make up genes.

When the DNA sequence in a gene undergoes a permanent change, a genetic mutation occurs. These mutations can vary in size from a single DNA base to a substantial part of a chromosome.

How Genetic Mutations Occur

Human genetic mutations can either be inherited from a parent (hereditary or germ line mutations) or acquired over an individual’s life span (acquired or somatic mutations). Hereditary mutations exist in almost every cell in a person’s body and are present throughout the individual’s life.

Occasionally, mutations occur exclusively in a sperm or egg cell, or they form immediately after fertilization. These are called de novo mutations, and they help clarify why a child may be affected by a disorder when there is no family history of the disease.

Somatic mutations occur in the DNA of specific cells at random points in time throughout a person’s lifetime. They can be caused by environmental factors such as poor diet, a sedentary lifestyle or ultraviolet radiation from the sun; or if an error occurs when the DNA strands copy themselves during cell division. These mutations will not be passed on to future generations.

How Genetic Mutations Affect Health

Genetic mutations in humans can affect a person’s health in positive or negative ways. The most common example of genetic mutations that cause disease is cancer, which is a result of a sequence of mutations in key regulatory genes.

Most cancers stem from a single mutated cell. As the cell divides, the new cells acquire different mutations and exhibit different behaviors. The cells then gradually become more abnormal as more genes are damaged. Many times, the genetic changes even spread to DNA-repair genes, leaving the other cells at risk for more damage.

Not all changes in genetic makeup are bad, however. In a recent study, 30 men with low-risk prostate cancer decided to forego traditional cancer treatments (radiation and surgery) and instead opted for simple lifestyle changes. They switched to a diet heavy in fruits, vegetables, grains, legumes and soy products. They engaged in moderate exercise and stress-relief practices.

Three months later, not only did these men lose weight and lower their blood pressure, but the researchers also noticed an astounding change in the activity of about 500 genes. The patients’ disease-preventing genes increased, while a large quantity of disease-promoting genes (including genes involved with prostate cancer and breast cancer) actually shut down.

If other studies support these findings, it’s possible that following a healthy diet and exercise program can actually cause genes to change in healthy ways to prevent disease, even if an individual has a genetic predisposition to these disorders.

Genetic Activity

Each cell has thousands of genes inside it. However, they are not all active at the same time. Two biological procedures regulate gene activity:

  • DNA methylation, where cellular enzymes attach a tiny molecular decoration to a gene, deactivating it.
  • histone acetylation, in which a dormant gene is reactivated.

Although these changes cannot be passed on to future generations, they can last a lifetime in the affected individual. They can be significant if an important gene is deactivated, like the gene that protects against cancer.

It is currently unknown how much genetic activity is programmed from birth and how much is caused by environmental factors. However, some studies performed with identical twins have shown that twins separated at birth and raised in totally different environments with completely different lifestyles had more disparity in their genetic activity than twins who were raised together.

Resources

Dunham, W. (2008). Healthy lifestyle triggers genetic change: study. Retrieved September 17, 2008, from the Reuters U.K. Web site: http://uk.reuters.com/article/healthNews/idUKN1628897920080616.

Emory University Staff. (2007). Genetic change. Retrieved September 17, 2008, from the Cancer Quest Web site: http://www.cancerquest.org/index.cfm?page=53.

Genetics Home Reference Staff. (2008). What is a gene mutation and how do mutations occur? Retrieved September 17, 2008, from the Genetics Home Reference Web site: http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/genemutation.

Weiss, R. (2005). Twin data highlight genetic changes. Retrieved September 17, 2008, from the Washington Post Web site: http://www.washingtonpost.com/wp-dyn/content/article/2005/07/04/AR2005070400845.html.