Biomedical Engineering Reference
In-Depth Information
Chapter 3
RECOMBINANT DNA TECHNIQUES: CLONING
AND MANIPULATION OF DNA
A.
Introduction
Recombinant DNA refers to DNA that has been experimentally ma-
nipulated in a laboratory by adding or deleting genes. Recombinant DNA
is usually incorporated into vectors that can be introduced into bacte-
ria, so that the bacteria now contains the gene(s) of interest, genes
that they would not normally express. The advent of recombinant DNA
technology is one of the most significant developments of century
biomedical science. The ability to clone genes led to the establishment
of the Biotechnology Industry, which uses cloned genes for enzyme and
hormone replacement therapies. For example, before the advent of the
biotechnology industry, insulin was purified from natural sources, limiting
its availability. Now, it can be produced in essentially limitless quantities
and at significantly reduced cost. Recombinant DNA techniques are
used to establish new therapies for treating diseases, such as immun-
odeficiency diseases and metabolic disorders, and are also being used
for vaccine development. Recombinant DNA techniques have also sig-
nificantly enhanced our ability to analyze protein structure and function,
determine how genes turn on and off, and understand tissue specific
gene expression. The ability to clone DNA allows us to sequence DNA,
predict protein structure and experimentally prove function through pro-
tein expression and mutagenesis studies. The recombinant DNA rev-
olution has clearly had widespread application in both basic research,
and in medical applications.
The first successfully cloned recombinant DNA was by Goff and Berg,
who reported the successful construction of hybrid viruses in 1976 (19).
In fact, results of the study were known earlier, but their publication was
delayed and a moratorium was placed on recombinant DNA technology
until a study of its safety could be completed. As a result, most vectors
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