Think of your community's traffic. When the lights are functioning, drivers (usually) behave. Break a light, and everything comes to a standstill. Within our bodies, we could liken that broken traffic light to a DNA mutation -- one that has the potential to mess up our body's everyday operations. So where lightning might knock out a traffic light, what causes DNA mutations?
First, you need an understanding of what DNA is. DNA is composed of four chemicals: cytosine, guanine, thymine and adenine. Our cells are made up of DNA, which is strung together in chromosomes. We have our parents to thank for these chromosomes -- 23 pairs from each.
Genes, which make up our DNA, provide directions for producing our body's proteins. These proteins are vital to survival. They provide function, regulation and structure for our tissues and organs. So if you mess up those directions through a genetic mutation, you might put a needed protein at risk. What's behind a mess-up? We can point fingers at two main culprits: mistakes in cell replication and environmental causes.
Because we continually need new cells, our DNA replicates itself. During this duplication process, errors sometimes occur. During replication, double strands of DNA are separated. Each strand is then copied to become another double strand. About 1 out of every 100,000,000 times, a mistake occurs during copying, which can lead to a mutation. We can certainly take comfort in that statistic, as well as the fact that our DNA does a stand-up job of repairing itself when mutations occur [source: Learn. Genetics. Genetic Science Learning Center].
Mutations can also be caused by environmental foes. Tobacco, ultraviolet light and other chemicals are all potential enemies of DNA. One way these hazards attack our genes is very sneaky: They have the ability to damage the chemicals making up DNA. For example, the mutagens like to swap the chemicals out or disguise one for another. This becomes a big deal when our DNA starts replicating itself because those chemicals don't behave correctly [source: Learn. Genetics. Genetic Science Learning Center].
This type of environmental mutation is referred to as a substitution. Two other examples of the many types of DNA mutations are:
- Deletion, when a section of DNA is deleted, meaning part of the recipe for making a protein is completely gone.
- Insertion, when extra genetic code is inserted. This is like adding an extra ingredient to a recipe for cookies and hoping they still turn out right.
When you think of the multiple ways our DNA can mutate, it can seem scary. Bur remember, a lot is happening with our 25,000 to 35,000 genes [source: TeensHealth]. Sometimes, mutations don't matter at all, or they can help us evolve in helpful ways. Think of when that traffic light is out on your street. Likely, you still make it to your destination. You slow down and watch for oncoming traffic. You become your own advocate. That's just what we can do when it comes to our DNA. There's a world of life taking place inside of us, and we can cut down on power outages through healthy habits and watching out for our well-being.
- Learn. Genetics. Genetic Science Learning Center. "What Causes DNA Mutations?" May 28, 2010. (September 20, 2010) http://learn.genetics.utah.edu/archive/sloozeworm/mutationbg.html
- TeensHealth. "The Basics on Genes and Genetic Disorders." April 2009. (September 20, 2010) http://kidshealth.org/teen/your_body/health_basics/genes_genetic_disorders.html
- University of California Museum of Paleontology. "Understanding Evolution." (September 20, 2010) http://evolution.berkeley.edu/evolibrary/article/mutations_01
- U.S. National Library of Medicine. "Handbook: Help Me Understand Genetics." July 25, 2010. (July 26, 2010)http://ghr.nlm.nih.gov/handbook