Genetic factors in disease. Conceptual image of genetic screening showing a DNA autoradiogram projected onto the back of a naked woman. Autoradiograms show the genetic sequence of DNA (deoxyribonucleic acid). This sequence is unique for every individual. Certain conditions, such as breast cancer that affects five percent of the female population, have been linked to genetic factors. If these conditions could be diagnosed before symptoms occur using DNA screening programmes, many lives could be saved.