The use of scientific and
engineering principles to manipulate organisms or their genes is Biotechnology.
The classical biotechnology involves selection hybridization and mutation. For
more than 8000 years bacteria yeast have been used to produce beers, vinegar,
yogurt and cheese. Since ancient times, plants and cheese. Since ancient times,
plants and animals breeders have selectively bred organisms to develop hybrids.
In the late 1920s, scientists induced genetic mutation and obtained plants with
new characteristics. The United Nations
Convention on Biological Diversity (UNCBD) defines biotechnology as:
“Any technological application
that uses biological systems living organisms or derivatives thereof, to make
or modify products or processes for specific use”. In other words “Application
of scientific and technical advances in life sciences to develop commercial
products” is biotechnology. A revolution took place in this area after the
discovery of molecular structure of the hereditary material deoxyribo-nucleic
acid (DNA).Another important landmark is the discovery of restriction enzymes.
These are made by bacteria as a defense mechanism against viruses. Restriction enzymes bind to specific
sites (restriction sites) of viral DNA and restrict the growth of virus by
cutting the DNA into small fragments (fig.B.3.5). these enzymes can be used to
cut any DNA to produce small fragments of DNA, which can be separated by size
using Gel electrophoresis. Specific DNA sequence can be identified in a gel by
probes with a complementary sequence using Southern
Blotting technique.
Blotting technique.
The action of restriction
endonuclease (EcoR I) of DNA. The enzymes make sticky ends which helps to make recombinant
DNA.
Recombinant DNA is formed by the combination of two DNA from
different source. One of the major goals of recombinant DNA technology is to
clone a particular gene. Bacteria, yeasts and cultured plant cells are commonly
used as hosts for recombinant DNA. Host cells into which recombinant DNA is
inserted, or transformed, are called transgenic
cells. To identify host cells that have taken up a foreign gene, the
inserted sequence can be tagged with reporter genes genetic markers with easily
identifiable phenotypes. Expression of the foreign gene in
the host cell requires, so that it can become the part of a segment of DNA, a
replicon (origin and terminus of replication). There are two general ways in
which the newly introduced DNA can become part of a replicon.
It can be inserted
near on origin of replication in a host chromosome after entering the host
cell.
It can enter the
host cell as a part of a carrier DNA sequence called vector that already has
the origin of replication.
Plasmids, viruses and artificial
chromosome (YAC – yeast artificial chromosome, BAC- Baxterial artificial
chromosome) are all used as vector. DNA for cloning can be obtained from gene
libraries, cDNA made from mRNA, and artificial synthesized DNA fragments.
Biotechnology has applications in four major industrial areas, including
health care, crop producer products (e.g., biodegradable plastics, vegetables
oil, biofuel) and environmental uses.
The several branches of
biotechnology are:
Bioinformatics: It is also referred to
as computational biology I and defined as “conceptualizing biology, in terms of
molecules and then applying informatics techniques to understand and organize
the information associated with these molecules, on a large scale”. It is an
interdisciplinary field which solves biological problems using computational
techniques and analysis of biological data. It plays a key role in functional genomics, structural genomics
and proteomics and forms a key
component in the biotechnology and pharmaceutical sector.
Blue Biotechnology: The term uage is
relatively rare. It is used to describe the marine and aquatic applications of
biotechnology.
Green biotechnology: It is the
application of biotechnology to agricultural processes. It includes micro-
propagation, transgenic plants and industrial agricultural. An example of this
is the engineering of a plant to express a pesticide (Bt cotton).
Red biotechnology: It is applied to
medical processes. Designing of organisms to produce antibiotics, and the
engineering of genetic cures through genetic manipulation.
White Biotechnology: It also known as
industrial biotechnology. It involves the use of enzymes as industrial
catalysts to either produce valuable chemicals or destroy hazardous polluting
chemicals
The investment and economic output tall these types applied bio technologies is termed the bio-economy.
Genetic engineering: Human has alerted the genomes of species for
thousands of years through artificial selection. In 1986, tobacco plants were
engineered to be resistant to herbicides and the first field trials of
genetically engineered plants we done. The basic steps involved in genetic
engineering are (Fig.B.3.6)
·
Isolation
of the gene: The gene to be interested into the genetically modified
organism must be chosen and isolated. Most of the genes transferred into plants
provide protection against insect or tolerance to herbicide. The gene can be
isolated from gene library or artificially synthesized. The gene is then
inserted into bacterial plasmid.
·
Cloning
Vectors: The gene is inserted into other genetic elements for its proper
functioning. The gene to be inserted must contain a promoted and terminator
region as well as a selectable marker gene. The promoter region initiates
transcription of the gene, while the terminator region ends transcription. The
selectable marker, antibiotic resistance, helps to determine which cells are
transformed with the new gene. The constructs are made using recombinant DNA
techniques, such as restriction digest, ligations and molecular cloning.
