ABSTRACT
In the late 1960s, human biology was in the midst of an unprecedented knowledge explosion. Following on the discovery of the structure of DNA by James Watson and Francis Crick in 1953, discovery after discovery followed that began to illuminate the mechanisms by which the DNA genetic information comprising the genes was expressed in both health and disease – how normally functioning genes regulated normal biology and normal human traits, and how defects or “mutations” in the genes were responsible for most human disease – “simple” single-gene genetic diseases such as cystic fibrosis and muscular dystrophy, and complex diseases involving many interacting genetic abnormalities such as most human cancers, diabetes, heart disease and hypertension, Alzheimer’s and Huntington’s diseases, schizophrenia, etc. It was clear for the first time that these errors were caused by abnormalities in the arrangement of the chemical subunits of DNA – the “bases” “sequence” of DNA – and that the abnormal arrangement of the bases caused the functional products of the genes – the proteins – to have abnormal structures. Such abnormal proteins could no longer perform their vital functions as enzymes, as building blocks of cells, as hormones, etc. and therefore would produce abnormal metabolic effects and disease.
