Catatan

Since the beginning of the last century, scientists
have been interested in genes. First, they wanted to
find out what genes were made of, how they worked,
and how they were transmitted from generation to

generation with the seemingly mythic ability to con-
trol both heredity and variation. Genes were initially

thought of in functional terms as hereditary units

responsible for the appearance of particular bio-
logical characteristics, such as eye or hair color in

human beings, but their physical properties were
unclear. It was not until the 1940s that genes were
shown to be made of DNA, and that a workable
physical and functional definition of the gene – a
length of DNA encoding a particular protein – was
achieved (Box 1.1). Next, scientists wanted to find
ways to study the structure, behavior, and activity of
genes in more detail. This required the simultaneous
development of novel techniques for DNA analysis
and manipulation. These developments began in
the early 1970s with the first experiments involving
the creation and manipulation of recombinant DNA.
Thus began the recombinant DNA revolution.