DNA sequencing is any process used to map out the sequence of the nucleotides that comprise a strand of DNA. This website is meant as a primer to show you, step by step, what parts of DNA are being 'sequenced' and why it is such a valuable process for humankind to learn. To do this, I need to give you a linear overview of DNA, starting with how the familiar double-helix DNA strand is structured. When you understand the components of that structure, you understand what DNA sequencing is trying to read. This works best if read in order; if you start with the 'DNA' page and work yourself down, by the time you arrive at the DNA Sequencing page you should have a pretty clear layman's picture of the constituent parts of DNA and what the parts are that are being sequenced. It is meant to give you a clear but layman's understanding of DNA and DNA sequencing, after which you can look into more technical resources elsewhere if you like.
DNA sequencing is a newer technology; it has been known since the invention of the microscope that some central part of the human cell (and animal and plant cells, any cell of a living organism) has as its core some small piece of information-holding matter that probably contains the blueprint of how each cell in your body is formed. In 1944 DeoxyriboNucleic Acid was discovered to be the chemical comprising this tiny central encyclopedia found in every cell, and the shortening to DNA became a household word.
The evolution of our discovering how DNA is put together has been the greatest contribution to our knowledge of ourselves physically. Scientists have invented and discovered increasingly revealing methods of opening the secrets of DNA; after the discovery of the double-helix shape of DNA in 1953 (see the DNA Sequencing page further down), and seeing how DNA is comprised of a series of ladderlike units known as DNA nucleotides, the primary goal has been to find out just how the sequence of those little nucleotides leads to whether you have blonde or red hair, whether you have light or dark skin, and every other detail from your bone marrow to the tips of your hair; DNA sequencing is seen as the looking glass into the origins of what makes every part of you, large and small, what it is. And DNA sequencing is the prime process by which scientists unravel genetics, the study of how we are put together and how we transfer our traits to our offspring. If finding DNA was the discovery of the exact subtance holding our genetic makeup information, DNA sequencing is the discovery of the process that will allow us to READ that information. Let's begin with DNA and carry through to DNA sequencing and its uses.