Chapter 16: The Molecular Basis of Inheritance Overview: Life?s Operating Instructions Watson and Crick introduced the double-helical model for the structure of DNA DNA is the substance of inheritance encoded in chemical language of DNA and reproduced in all the cells of your body it is DNA that directs the development of many different types of traits Concept 16.1: DNA is the genetic material The Search for the Genetic Material: Scientific Inquiry the role of DNA in heredity was first worked out by studying bacteria and the viruses that infect them Evidence That DNA Can Transform Bacteria Griffith worked with a pathogenic and nonpathogenic strain