The totality of a living organism's genes is referred to as its genome. The hereditary information of the human organism is coded into around three billion base pairs, which are divided into two sets of 23 chromosomes. The sequence of these DNA building blocks differs between two people approximately every 1,000 base pairs and it is this that accounts primarily for the genetic differentiation of individuals. The genetic difference compared to our nearest biological "relatives", chimpanzees, is roughly only 2 %.