DNA sequencing is a process where we figure out how some, or possible all, of the letters in your DNA are arranged. Unlike the alphabet that we use to write books, the language of your DNA is written using only four letters: A, T, C, and G. Most people have approximately 6.4 billion letters in their DNA (and that’s in almost every cell of your body). How those letters are arranged is nearly identical from person to person, with the exception of some 60 million differences between any two people (considering there is 6.4 billion letters, that’s a pretty small fraction). DNA sequencing technology allows us to read portions of your DNA and determine what the sequence of letters you have in that location. This type of information can help us learn about your ancestry, your likelihood of being lactose intolerant, or even your relative risk for developing certain diseases.