Genomic Instability
Hallmark of Aging #1
Why is our DNA so important? Most people have learned in high school biology that DNA is biology's code for life. People often talk about our traits like being tall or blond-haired or about our personalities such as introversion and extroversion being "in our DNA." Those simplified understandings of DNA are mostly true, but those heuristics overlook the unfathomable amount of complicated steps that human biology takes to translate our DNA code into our human characteristics.
The most important understanding of how DNA works is that DNA serves as the instruction manual for our body. This instruction manual tells our cells how to manufacture proteins. Proteins are the building blocks of all parts of our body. Our skin, our hearts, and our brains are all constructed from different combinations of proteins that interact with one another. Our DNA provides the innate knowledge for our body to know what proteins are needed and where.
Our "genome" is the term used to describe the entirety of our DNA code. Each person's genome consists of about 3 BILLION base pairs of DNA. Thus, one of the core factors that leads to human aging are alterations to our genome that cause this critical source code to become unstable. Genetic mutations result in "Genomic instability" that cause problems in the protein byproducts that are manufactured. This genomic instability is one of the root causes in the most deadly disease such as cancer or heart disease, and it is the 1st of the "Hallmarks of Aging." (I will cover each of the 9 Hallmarks of Aging in separate posts).
As we get older, the likelihood that our genome has accumulated more mutations is much higher. When we are young, our bodies are very good at preventing and correcting DNA mutations. But over the years, these DNA repair mechanisms become dysfunctional and DNA mutations slip by unnoticed, allowing errors in protein production to arise and to wreak havoc on parts of our bodies. We are exposed to all kinds of environmental and lifestyle threats throughout our lives that can lead to genomic damage. The most obvious threats include UV rays from sunlight and smoke from cigarettes, but even other biological threats like viruses or the foods we eat can create a cascade of biological changes that result in genomic instability.
Researchers and biotech companies are attempting to create and to test drugs, technologies, and lifestyle changes that could support our DNA repair systems and keep them functional for much longer. And of course, there are incredible amounts of research and investment ongoing to validate and to create genetic editing technologies such as CRISPR-Cas9 that make direct corrections to dysfunctional DNA sequences. We will cover these strategies to prevent genomic instability in several future posts.
As is the case with all of biology, scientists have only scratched the surface in understanding the exact nature of human genomes. The discoveries and technology breakthroughs are happening rapidly today, but the impact of this new knowledge is in its nascency. I am fascinated to follow the scientists and companies pushing human ingenuity around protecting and harnessing our source code of life. I surely will have much more to say about genomic instability and related topics in the future as I continue to do my own research and to learn more.
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Here are a couple excellent books to read if you are curious to learn more about the science and technology around DNA and genomics:
The Genome Odyssey: Medical Mysteries and the Incredible Quest to Solve Them by Dr. Euan Ashley
The Code Breaker: Jennifer Doudna, Gene Editing, and the Future of the Human Race by Walter Isaacson
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Images Credit: Created using software from Midjourney