Each human cell contains two sets of chromosomes, one from each parent. In these coiled bundles of DNA lie the entire set of instructions for the human body. Vast regions of DNA, however, do not seem to be directly involved in any genetic processes, and can therefore change drastically without effecting any part of human development.

In the paternity genetic tests shown here, a section of this “intragenic” DNA is isolated from the inside cheek cells of the artist and four members of her family. The isolated DNA is loaded into the small rectangular holes in the top of the gel shown, and electricity is run from one end of the gel to another using a saltwater bath. The dyed pieces of DNA are dragged through the gel by the electrical current, moving faster if they are small, and slower if they are large. In this way, different length fragments of DNA are separated from one another.

DNA Paternity Test

The horizontal bars in the gel image each represent a length of DNA fragment, with shorter fragments traveling further toward the bottom of the gel. Everyone has two different lengths of the fragment amplified in this test, and each person passes one of these segments to their offspring. Like the overwhelming majority of human genetic material, these intragenic repeat sections show no correlation to race or ethnicity, showing how genetic variation between individuals of one family far outweighs any differences that could be found across racial lines.

–Ben Duncan-Stoner, Research Scientist