The extraction of nucleic acids is the starting point in any molecular biology study and is thus considered a crucial process. The first crude extraction of DNA was performed by Friedrich Miescher, a Swiss physician, in 1869. He accidentally purified DNA from the nucleus while investigating proteins from leukocytes and found that the substance's property was fundamentally different from proteins and hence coined the term nuclein. DNA can be extracted from diverse sources, such as fineneedle aspirates of body fluids and biopsy samples; dried blood spots, buccal swabs, and fingerprints; soil, plant, and animal tissue forensic samples; and insects, protozoa, bacteria, and yeast.

Proteomics, also known as the large-scale study of proteins, involves the study of the structure and function of proteins and their interactions in the complex body. A proteome is a set of proteins present in either a cell, tissue, or organism, and its population may differ over time due to differences in gene expression. Proteomics investigates how different proteins interact with each other and the roles that they have within the organism, and assess the activities, modifications, and interactions of proteins within protein complexes to determine their function.