OK, if you read this blog you know that I love moments when medical or science dogma blows up. So I love that scientists recently found that what we thought we knew about DNA is wrong. They had me at helix. Let me explain.
DNA stands for deoxyribonucleic acid, and as I’ve explained before, it is the blueprint for life with each person having his or her own dedicated DNA sequence. In other words, unless you have an identical twin, your DNA doesn’t match anyone else’s. Recently, it’s also been discovered that even twins have slight differences in their DNA.
DNA has another function, heredity. It houses our genetic information passed down to us via chromosomes (the x-shaped structures in which DNA is packaged) from both of our parents. We get 23 chromosomes from Dad and 23 from Mom, which pair up to give us our own set of 23 chromosomes. These chromosomes live in each of our cells and carry the genetic code that determines everything from our physical appearance to our risks of hereditary diseases.
If I can take you back to science class for a moment, you might recall the double-helix DNA structure. In science we learned that a single DNA molecule looks a bit like a spiral-shaped ladder with the rungs consisting of pairs of chemical bases (adenine, thymine, cytosine, and guanine) and the side rails consisting of sugar and phosphate molecules. When our cells divide, an exact copy of our DNA is created. However, a new study has just made a fascinating discovery: a new DNA structure that we never learned about in science class. Let’s review.
Before the new study, researchers had been aware of the existence of this new DNA structure for a couple of decades; however, it had only been seen in vitro, or outside of living cells, in a lab environment. In the newest study, however, the significant finding was that this new DNA structure named intercalated motif (i-motif) was found inside living human cells, not just in artificial conditions in a lab environment.
Visually described by one of the scientists as a “four-stranded knot,” the i-motif DNA structures appear to be transient, coming and going as the cell needs. Also, in the traditional double-helix structure, cytosine, for example, binds to guanine when the chemical bases from the two strands pair up; however, in the i-motif, cytosines on the same strand will bind to each other.
Finding a totally different DNA structure in living human cells means that the chances of eventually finding alien life just got that much bigger. Why? Life as we know it had depended on one narrow type of molecules arranging in a very specific pattern. Now it turns out that the way these molecules arrange isn’t as important as we thought. Hence, other combinations and permutations may be compatible with life.
While DNA in some form has been studied for well over a century (in the late 1800s, it was called nuclein), it wasn’t until the 1950s that the DNA structure we are all so familiar with, the double helix, was identified. And it’s only over the last couple of decades that DNA has become so critical to everything from crime solving to testing for genetic diseases to everything in between and beyond as DNA research now seems to progress at a rapid speed.
I recently covered a study that found that while we may be created with a genetic DNA blueprint, environmental factors can alter our gene expressions, making us a product of both our genetics and our environment. An example of this is found in another study that concluded that the acetaldehyde in alcohol (an environmental element) can actually break the DNA in stem cells, and if the body does a poor repair job on the cell, this can lead to gene mutations that can increase the risk for cancer.
On the other hand, the genetic code carried in our DNA may benefit from positive influences as well. For example, one study found that our genes evolve to protect us from genetic variations and mutations thereby reducing or even eventually eliminating certain diseases.
The upshot? A four stranded knot? I love this study! Why? It just blew out of the water this idea we all had about the elegance and specialness of our DNA. Turns out that nature has a sense of humor!
About the Author
Christopher J. Centeno, M.D. is an international expert and specialist in regenerative medicine and the clinical use of mesenchymal stem cells in orthopedics. He is board certified in physical medicine as well as rehabilitation and in pain management through The American Board of Physical Medicine and Rehabilitation.…