MODEL RELEASED. Gene sequencing. Female technician studies banded DNA sequences or insgenetic fingerprintsins on an autoradiogram. She is determining the base sequence that forms the genetic code for a section of DNA (deoxyribonuc- leic acid). The DNA sample was cut into fragments by an enzyme and marked with radioactive tags for sequencing. These fragments were then placed in an agarose gel and separated by electrophoresis, the application of an electric charge, causing the fragments to move at different rates. An autoradiogram of the resulting bands of radioactively-tagged DNA was produced by placing a radiographic film on the agarose gel.