What exactly is DNA?

By Sainabou Laye Ndure, Founder, Human Genetics Awareness Association (HuGAA)

& Commonwealth PhD Scholar (QMUL, PHURI)  

Introduction

Every living thing you have ever seen, every plant, animal, and human, is written in the same ancient language. A language made not of words or symbols, but of four tiny letters: A, T, C, and G. This is the language of life itself, and it lives inside you.

I personally think the use of the word DNA has been increasing lately, and I love it. We, as a people, are becoming more aware, more informed, and more intentional about making the right decisions for ourselves.

Individually, we are all unique, thanks to our DNA. From now on, I will refer to it as our biological blueprint, because that is exactly what it is. It holds the maps, the signs, the models, the manual, and all the information that allows us to function as individuals and as a whole species.

The Science Behind It

To get a bit scientific, DNA stands for Deoxyribonucleic Acid. It is made up of three key components:

1.     A sugar molecule called deoxyribose

2.     A phosphate group

3.     A nitrogenous base (A, T, C or G – more on those soon)

These sugars and phosphates form the backbone of DNA, while the bases act as the letters of the code. The phosphate end bonds with other nucleosides to form a phosphodiester bond, and this happens repeatedly until the chain becomes millions of units long.

This creates a single DNA strand. However, in the average cell, DNA exists as a double helix. It is a structure I find quite elegant as it shows how each strand is complemented by an opposite strand. These two strands are held together by hydrogen bonds between their bases, forming that beautiful spiral staircase shape we all recognise.

Where Does Our DNA Come From?

Half of your DNA comes from your father, and half comes from your mother. Together, they combine to form a new, unique sequence that has never existed before. When DNA copies itself to make more DNA for new cells, the process is called replication. During replication, the two strands separate: one becomes the leading strand, and the other the lagging strand. This naming depends on how the nucleotides (the A, T, C and G bases) are arranged and on where the phosphate bond sits on the sugar molecule.

DNA is always read in a 5 prime to 3 prime direction; these numbers refer to the positions of the hydroxyl (OH⁻) group on the sugar. Think of it like reading a sentence in one direction so that the message stays consistent.

How Does DNA Replicate?

Hope I’ve not lost you yet!

Replication might sound complicated, but it is actually a beautifully coordinated puzzle. This process is facilitated by an enzyme called DNA polymerase, an expert puzzle solver that adds the correct base to the right place every time.

There are four main bases that DNA polymerase works with:

·       Adenine (A)

·       Thymine (T)

·       Cytosine (C)

·       Guanine (G)

And here is the rule:

·       Adenine always pairs with Thymine

·       Cytosine always pairs with Guanine

That is all there is to it. These bases line up along the DNA strand in a precise sequence that contains the body’s entire instruction manual. It is within these sequences that the body reads and uses information to make proteins, the working molecules that build, repair, and regulate everything from your skin to your blood cells.

The Double Helix – A Masterpiece of Nature

In summary, DNA is a double helix, two strands wrapped around each other, holding the entire story of life. It encodes long series of A, T, C and G arranged in an exact order that the body reads whenever it needs to perform a specific function.

It is like having a recipe book so detailed that every cell knows exactly what to prepare, when to prepare it, and how to serve it.

Why It Matters

Understanding DNA is not just about science; it is about knowing yourself. Your DNA determines your unique traits, from eye colour and hair texture to your health risks and even how your body responds to food or medicine.

Knowing this helps us appreciate how alike we all are. Humans share about 99.9 percent of their DNA, yet that tiny remaining difference holds our individuality.

By understanding DNA, we can:

·       Trace our ancestry

·       Detect and prevent inherited diseases

·       Develop personalised medicine

·       Celebrate our shared humanity

That is the heart of why I started this series – to help you see that genetics is not something to fear or ignore, but something to understand and embrace.

 What Comes Next

So that is it for DNA, the double helix that carries life’s blueprint. But this is just the beginning. Next, we will explore:

·       Epigenetics: how the environment influences the way your DNA behaves

·       Gene expression: how your body reads and uses your DNA

·       Genetic errors: what happens when the code makes a mistake

Whichever topic comes next, I promise to keep it simple, interesting, and above all, human. 

This article is part of HuGAA’s Make it Easy! – Genetics Simplified series, where we turn complex genetic science into clear, everyday stories that everyone can understand.

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