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In case you thought DNA was a subject only for science classes and high-tech laboratories, think again! You can isolate a lump of DNA in your own kitchen, using a common onion. Imagine the conversations you can have—after you wipe the tears from your eyes.
We are all familiar with the term DNA (DeoxyriboNucleic Acid), but most people probably think of it as an abstract idea that has little to do with daily life. The experiment on the next page may change that view.
DNA is all around us. It is found in every plant and animal. You literally eat it at every meal. It is possible to extract pieces of DNA, consisting of billions of basic units (called “bases,” abbreviated as A, C, T, and G), with just a common onion and a few household chemicals.
It is amazing what you can hold in your hand. Each DNA strand is an extremely long molecule. While humans have about 3 billion bases in their DNA, the garden onion (Allium cepa) has 15 billion bases. If the DNA in a single human cell were stretched out it would be 6 feet (1.8 m) long, so imagine how long the DNA from an onion cell would be!
DNA is found in every living cell (at least that we know of). It is like a recipe book providing information for building and running the organism. Because each organism needs different information, the arrangement of DNA varies in each individual. Human DNA must contain information to make brains and eyeballs, while plant DNA provides information to make leaves and roots (such as onions).
God gave every kind of creature some unique DNA. Yet similar organisms often have similar DNA because they perform the same tasks. For example, both cats and dogs need DNA for making legs and tails, and vegetables and fruits need DNA for growing roots and stems.
Despite the differences, most living things perform some similar functions. For this reason, even human DNA has some similarity with an onion’s DNA. And that’s a good thing! Your body can easily break down the sugars and other molecules in the onion to build molecules for itself.
After doing our experiment extracting DNA from an onion, it looks like a messy glob. But that’s not how DNA appears in cells. DNA is neatly stored in a small compartment called the nucleus. The DNA is folded up many, many times so it can fit in the nucleus.
This folding is not random but carefully controlled and specific. To give you an idea about this marvel of packaging, imagine folding a long spaghetti noodle—stretched across the entire United States—and storing it in a small box so that any portion can be unfolded, copied, and used at any time. That’s the wonder of DNA.
The DNA molecule is often compared to a book. The DNA bases (A, C, T, and G) form words called genes. The genes contain all sorts of information necessary for life. As we continue to learn more about this wonder, we can appreciate the wisdom and goodness of the author, God. He is the author of life, who created DNA to provide the information necessary for the development and growth of living organisms, including you and me.
Think about this the next time you eat an onion!