A discipline that deals with the origins and mechanisms of diseases at their most fundamental level, that of macromolecules such as deoxyribonucleic acid (DNA) and protein, in order to provide precise diagnoses and discover possible avenues for treatment. It is interdisciplinary, including infectious disease, oncology, inherited genetic disease, and legal issues such as parentage determination or forensic identity testing. While a variety of biophysical and biochemical techniques can be applied to study the molecular basis of disease, antibodies and nucleic acid probes are two of the principal approaches.