The role and function of DNA

Alex Auld


April 4, 2023

To best understand how insights into your genome can be used to tailor your health and fitness, it’s important to recognise what DNA is and how it works. 

Although a full understanding of genetics requires much greater explanation and detail than a blog allows, we hope this introduction to some key concepts will provide the scientific foundations for you to build upon. Let’s get started. 

What is DNA?

DNA (or deoxyribonucleic acid, to give it its full name) is life’s hereditary molecule. It’s the biological information that is passed down between generations, influencing the way we look, develop, and respond to our environment. 

You’re likely familiar with the double helix structure of DNA. If unwound, this structure would look like a ladder, with two sugar-phosphate strands on either side connected by nitrogen base pairs. Each nitrogen base, sugar, and phosphate molecule on a strand forms a building block known as a nucleotide. There are four different nucleotides in DNA, which correspond to the four different nitrogen bases they have:

  1. Adenine (A)
  2. Thymine (T)
  3. Guanine (G)
  4. Cytosine (C) 

Crucially, adenine is always paired together with thymine, and guanine is always paired with cytosine. Why that’s crucial will become apparent later on. 

Transcribing DNA into RNA

Alongside the development of new cells, a primary function of DNA is to code for the production of proteins. And not just proteins that help you to build muscle - they may be enzymes that carry out vital reactions in your body, antibodies that help you to fight disease, or neurotransmitters that send messages to and from the brain. Proteins are involved in virtually every biological process. 

To produce new proteins, DNA needs to be read. First of all, the DNA molecule is unzipped. One of the unwound strands is then used as a template, whereby complementary nucleotides are added to create a strand of RNA (or ribonucleic acid). The process of reading DNA and making it into RNA is known as transcription. 

After some editing and tidying up of the RNA molecule, it is ready to be read and made into protein. 

Translating RNA into proteins

So how does the strand of RNA produce the proteins that we need to function and grow? This process is known as translation and begins by reading the sequence of nucleotides in the RNA strand. Specialised machinery in our cells, known as ribosomes, read the nucleotide bases in groups of three, known as ‘codons’, with each codon associated with an amino acid. 

For example, the three-base codon CGC is associated with the amino acid arginine, while ACA represents threonine. As amino acids are the building blocks of proteins, their sequence determines the properties of the protein that is produced and therefore its influence on the body. 

This chain of communication, from the original base sequence of DNA all the way to the protein produced is known as the ‘central dogma’. 

The effect of genetic variation

We hope that now you have a grasp of the function of DNA, the effect of variation in the nucleotide base sequence between individuals will be apparent. 

Single changes within the nucleotide base sequence can cause a cascading effect, with the codon, amino acid sequence, and resulting protein all potentially affected. Other changes that don’t necessarily affect the properties of proteins can still be useful markers in identifying differences in how our bodies behave. 

By understanding how your unique base sequence influences the production and activity of certain proteins and acts as markers of how your body functions, we can better predict the health and fitness strategies that you are most likely to respond to. 

If you are interested in learning more about the causes and effects of genetic variation, we recommend reading our follow-up blog What Is Genetic Variation And How Does It Occur?

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Alex Auld

One of FitnessGenes' first full-time employees, Alex re-joined the company in 2021 after completing his MA in Global Communications at the University of London. He now oversees all customer communications, helping to ensure that our members get the most from their results. An amateur triathlete, you can expect to find him in the pool, on the bike, or running laps of his local park most weekends.

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