2. Trends in the Development of
Recombinant DNA Technology
• Our knowledge of the living cells date to 1665 when Robert Hooke described the
spaces he observes in a slice of cork. In 1838 and 1839, Schleiden and Schumann
formulated the cell theory which shows that the cell is the basic organization unit of
the living organism.
• The foundation for what is now known as Recombinant DNA Technology or
Genetic engineering was laid by Watson and Crick (1953) in the British Journal
“Nature”.
• Armed with these three types of enzymes: reverse replication, DNA ligase and
restriction endonuclease. Scientists now have the ability to create new forms of life
by splicing together DNA (or genes) from various source.
3. Genetic Cloning
• Cloning technology is widely expected to contribute to the stable supply of
livestock food sources, to the manufacture of pharmaceutical products, to the
protection and reproduction of rare animals and to mass production of test
animals.
• Benoaji (2000) defined cloning as the isolation and proliferation of individual
genetically unique cells, it is a kind of high resolution separation method for DNA
molecules which could be difficult to resolve by any other means.
• The word “clone” was first used to describe the population of cells or organisms,
all derived from a single cell or organism by asexual multiplication.
4. Advantages of Recombinant DNA
Technology
• Made it possible to obtain large amounts of particular genes to determine the
functions of segments of nuclear and organellar DNA and to map genomes.
• It can be used to synthesize large quantities of antibiotics, enzymes and (insulin)
hormones.
• The technology made it possible to cure diseases which for a long time have
afflicted mankind.
• It has also been used to achieve tremendous advances not only in the field of
medicine.
• Cloning from higher plants, micro-organisms, animals including mammals is now
achievable.
• It also benefited the couple(s) who are rendered infertile by one thing or the other
can now clone and produce their own child through test-tube babies.
5. Disadvantages of Recombinant
DNA Technology
• Large scale production of cancer-causing viruses.
• The creation of penicillin-resistant recombinant E. coli.
• It requires and expert in the field to carry out the cloning.
• Human being, if cloned by asexual reproduction may be denatured.
• Not all those who may need can afford it.
6. The Future of Recombinant DNA
Technology
• A sheep named “Dolly” was successfully cloned by a group of scientists at
the Roslin Institute in Edinburgh headed by Dr. Ian Wilmut.
• Two rhesus monkeys were cloned by another group of scientists at the
Oregon Regional Primate Research Center in the United States.
• In 1973, the technique of Invitro-fertilization (IVF) usually referred to as “test-
tube babies”. Test tube babies are done and presently couples who cannot
reproduce sexually are now able to reproduce asexually through the process
called clonal reproduction.