A look at the most common forms of damage to our DNA and how that damage can affect our bodies.

Quick Facts about DNA

99.5% of your DNA is shared with every other person on the planet!

The structure of DNA was discovered in 1953 by James Watson and Francis Crick.

DNA’s chemical makeup:

Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)

DNA Damage vs. DNA Mutation

DNA Damage

Recognized by enzymes > Correctly repaired > Replicates healthy DNA

DNA Mutation

Not recognized by enzymes > Cannot be repaired > Replicates mutated DNA

Note: Errors during replication or repair of damaged DNA can turn into mutation.

Exploring 4 Types of DNA Damage

Oxidative Damage

Oxidative stress occurs when the body is exposed to too many electrically charged, aggressive oxygen compounds.

How are we exposed?

Breathing
Ongoing stress
UV light
X-Rays

Why is it bad?

High levels of oxidative stress can overwhelm the body’s natural defenses and destroy genetic material, resulting in 8-hydroxydeoxyguanosine (8-OHdG), a common marker for oxidative damage.

Possible effects

Decreased DNA repair
Increased susceptibility to cancer (colon, breast, prostate)

Hydrolytic & Metabolic Damage

Hydrolytic and metabolic processes can naturally result in DNA damage. These naturally occurring damages take place in our bodies more than 60,000 times per day!

How does it happen?

Biochemical reactions of various metabolites
Overabundance of reactive oxygen species (ROS)
ROS: chemically reactive molecules containing oxygen

Why is it bad?

This type of damage contributes to a loss of DNA bases called AP (apurinic/apyrimidinic) sites, which are easily mutated.

Possible effects

Inhibited transcription

Replication of mutated cells
Progression of cancer

DNA Strand Break Damage

Strand breaks can occur in one or both of the DNA strands due to ultraviolet light and other types of radiation.

UV-Induced Damage

UV-B light > pyrimidine dimers > direct DNA damage
Occurs in areas on the body that are directly exposed to UV-B light
UV-A light > free radicals > indirect DNA damage
Absorbed into Chromophore and travels though body with potential to affect other areas of body (even inner organs)

Possible Effects

Mutations
Inhibits expression of multiple genes
Progression of skin cancers

Toxic Pollutant Damage

How does it happen?

Exposure to polycyclic aromatic hydrocarbons (PAHs) which are potent atmospheric pollutants. The following are examples of damaging pollutants.
Oil
Coal
Cigarette smoke
Automobile exhaust fumes

Possible Effects