Our entire body runs on instructions—written in the form of DNA, a long, complex molecule that lives inside nearly every cell. Genome sequencing is the process of reading the complete set of these instructions—three billion base pairs—known as the genome.

What makes this remarkable is not just the scale, but the detail. While most of our genetic code is shared with others (and even with bananas, surprisingly), it’s the small differences—called single nucleotide polymorphisms (SNPs)—that make each of us biologically unique.

_{Most SNPs don’t affect your health at all—but a few can make a huge difference. One SNP can determine whether a drug works for you, or whether you’re at high risk for a genetic disease. Researchers are still uncovering which ones matter most, and it’s changing how we treat illness.}

Genetic Traits and Characteristics

These variations influence everything from our eye colour to how we digest certain foods. For instance, some people carry a variant near the LCT (lactase-phlorizin hydrolase) gene that allows them to digest lactose—the sugar in milk—even into adulthood, while others gradually lose this ability and become lactose intolerant.

Certain gene variants can even shape physical performance. The ACTN3 (Alpha-Actinin-3) gene, for example, has been linked to fast-twitch muscle fibres—ideal for sprinting and power-based sports. Meanwhile, our immune responses, too, are influenced by our genes, affecting how we recover from infections or respond to vaccines.

_{Your immune system has its own ‘ID check’ system—and it's written in your DNA. The HLA (human leukocyte antigen) genes help your body recognise what belongs and what doesn’t, acting like bouncers at the door of your cells. But because everyone's HLA profile is slightly different, your body might react to infections, viruses, and even vaccines in a totally unique way compared to someone else.}