man and woman doing laboratory works

A Black male scientist is instructing a Black female high school student in the procedure of "southern blotting". Single strands of DNA are transferred onto a nitrocellulose filter, exposed to a radioactive labelled probe, which then sticks, or hybridizes, to a specific DNA sequence. These hybridized sequences will then give off a radioactive signal that can be visualized by exposing the filter to x-ray film, a procedure known as autoradiography.