All living things have a genome. In humans, this is all our DNA and contains the instructions to build and repair our bodies.
Genes account for just 2% of our complete set of genomic information, known as our genome, which it its entirety comprises more than 3 billion 'letters' of DNA.
DNA is made up of four chemical bases, known as A, T, C and G. If you said one letter of DNA per second, 24 hours a day, it would take 100 years to recite your whole genome.
Human genomes are around 99.9% the same. Sound pretty similar, right? But that actually equates to around 3 million differences between one person and the next.
Many of the differences in our DNA - known as variants - have no impact, but some can affect our health. Variants may cause a genetic condition, such as sickle cell anemia, or could influence our predisposition to develop a condition, such as breast cancer.
In healthcare, a person's genomic information can sometimes be used to diagnose a condition, predict and prevent disease, and offer personalised treatment.