In DNA testing DNA analysis is done by what is known as Short Tandem Repeat analysis. DNA is examined in short sections and differences between sections can allow for the distinction between unrelated/related individuals. It is important to note, that we share the larger bulk of our DNA with the rest of the population so these sparing variations in DNA can be extremely important. The likelihood of two unrelated individuals having exactly the same DNA is impossible unless they are identical twins. STR DNA analysis locates repeated DNA motifs; DNA motifs which consist of the base pairs: adenine, guanine, cytosine and thymine. Discrimination between individual becomes more thorough the more STR regions are taken under examination in a DNA test.