0 13 The Molecular Basis of Inheritance Overview: Life?s Operating Instructions In 1953, James Watson and Francis Crick introduced an elegant double-helical model for the structure of deoxyribonucleic acid, or DNA DNA, the substance of inheritance, is the most celebrated molecule of our time Hereditary information is encoded in DNA and reproduced in all cells of the body (DNA replication) Figure 13.1 Concept 13.1: DNA is the genetic material Early in the 20th century, the identification of the molecules of inheritance loomed as a major challenge to biologists The Search for the Genetic Material: Scientific Inquiry