What Is the Genetic Theory of Aging?

How Genes Affect Aging

Portrait of senior woman in kitchen
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Your DNA may predict more about you than the way you look. According to the genetic theory of aging, your genes are responsible for how long you'll live. Here's what you should know about genes and longevity.

Genetic Theory of Aging

The genetic theory of aging states that lifespan is largely determined by the genes we inherit. According to the theory, our longevity is primarily determined at the moment of conception, and is largely reliant on our parents and their genes.

The basis behind this theory is that segments of DNA that occur at the end of chromosomes, called telomeres, determine the maximum lifespan of a cell. The more repeats in a telomere, the longer the cell will live, since repeats are lost each time the cell divides. Eventually, the cell can no longer divide and dies.

Evidence Behind the Theory

There is some evidence to support this theory. Research indicates that telomeres are vulnerable to genetic factors that can speed up the rate of aging. In addition, people with parents who have lived long lives are more likely to live long themselves. However, this this could be partially explained by learned behaviors, such as food preferences and other lifestyle habits. 

Another indicator that genes affect aging is that identical twins, who have the exact same genes, have closer lifespans than siblings who are not twins.

How Genes Impact Lifespan

Some genes are beneficial and enhance longevity.

For example, the gene that helps a person metabolize cholesterol would reduce a person's risk of heart disease. But some genes are harmful, like those that increase the risk of cancer.

Some gene mutations are inherited, too, and may shorten lifespan. However, mutations also can happen after birth, since exposure to toxins, free radicals and radiation can cause gene changes.

Most mutations are not bad for you, and some can even be beneficial. That's because genetic mutations create genetic diversity, which keeps populations healthy. Other mutations, called silent mutations, have no effect on the body at all.

However, sometimes genetic mutations can cause significant harm. Various disease and conditions, which can all negatively impact lifespan, can be attributed to genetic mutations. These include cystic fibrosis, sickle cell anemia, Tay-Sachs disease and Huntington's disease, to name a few.

The Bottom Line

It is estimated that genes can explain a maximum of 35 percent of lifespan. The other determinants are your behaviors, exposures,and just plain luck. So don't think that you are doomed just because your family members tend to die young. And don't think that you can ignore your health if your family members tend to live long.

There are many more theories about why we age. For more information about other theories of aging, take a look at these helpful articles:

Programmed Theories of Aging​

Rate of Living Theory of Aging

Telomere Shortening - The Secret to Aging?

The Basics of the Immunological Theory of Aging

Theories and Effects of Aging

The Wear and Tear Theory of Aging

What Is the Cross-Linking Theory of Aging?

What Is the Somatic Mutation Theory of Aging?


The American Federation for Aging Research. How Do We Age?

Sacher, G. A. (n.d.). Aging: Life Process. Retrieved March 14, 2016, from Encyclopedia Brittanica Online.

The Tech Museum of Innovation. (n.d.). Mutations and Disease. Retrieved March 14, 2016.

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