CHAPTER 4Genes and the History of Molecular Biology
The molecular building materials for life are the biological molecules
discussed in Chapter 3: lipids, proteins, carbohydrates, and nucleic
acids. The same twenty amino acids are used by all life on Earth to
construct proteins, and the structures and functions of proteins are
similar all the way from single-celled bacteria to animals composed
of trillions of cells. Genetic information is stored in nucleic acid mol-
ecules (DNA and RNA) according to the same universal code, used
by viruses, bacteria, and human brain cells. The elucidation of the
mechanism of information storage, readout, and replication in living
organisms is one of the great tales in the history of science. Now, for
some of the backstory.
Observant humans have appreciated for thousands of years that
characteristics of organisms are carried through from one generation
to another in systematic ways. Selective breeding of animals gave
rise to domesticated pets (dogs and cats), cattle, and horses. Selective
breeding of plants produced cereal grains for brewing beer and mak-
ing bread; fruits and vegetables of many different shapes, sizes, colors,
and flavors; and cannabis for fiber and medicine. In the mid-1800s
Charles Darwin (1809-1882) introduced revolutionary new thinking