Colligative properties are those properties of solutions that depend on the number of dissolved particles in solution, but not on the identities of the solutes. For example, the freezing point of salt water is lower than that of pure water, due to the presence of the salt dissolved in the water.
Shares & Saves. Save. DNA testing evolved from the study of genetics, which began in the late 1800s when Gregor Mendel first studied the phenomenon of inherited traits in pea plants. His work laid the foundation for the discovery of DNA, or deoxyribonucleic acid, the molecules that contain our genetic makeup.
A brief treatment of DNA follows. For full treatment, see genetics: DNA and the genetic code. The chemical DNA was first discovered in 1869, but its role in genetic inheritance was not demonstrated until 1943. In 1953 James Watson and Francis Crick determined that the structure of DNA is a double-helix polymer, a spiral consisting of two DNA strands wound around each other.