What is DNA?

DNA in its simplest terms are the basic building blocks of life. As humans we have 3 billion pairs of DNA molecules (nucleotides) that encode everything needed for us to be alive, at a molecular level. DNA molecules come in the form of only 4 letters, A, T, C, and G. These letters normally only pair in two ways A pairs with T and C pairs with G. By reading this long string of letters we can decipher meaning from their arrangement. By comparing two humans string of DNA we can see a lot of similarity, however around 0.1% of the sequence is typically different. These differences can create visible differences like hair or eye colour, but it can also show differences in your risk for developing a health condition or a sensitivity to gluten for example.

Differences in DNA

The number of DNA molecules and their arrangement are different among species, but they also still share some similarities. We have more similar DNA to other humans than we have to dogs, but we do share some of the same DNA patterns with our canine friends. The increase in differences between species and the longer our species have diverged on the evolutionary tree shows greater differences in DNA. Typically when we share similar DNA patterns with other species it means that it is an important part of maintaining life – an essential component. When we recognize DNA patterns they are often what are called ‘genes’, these sections of DNA encode instructions for the cells of our body to make molecules that perform actions that keep us alive. When these instructions are “read” by cellular mechanisms they create RNA, which then creates proteins, which typically cause the changes we see. The above mechanism of DNA being used to make RNA being used to make proteins is referred to as the ‘central dogma of biology’. To read more about genetics and sequencing explore our other learn pages.