What is Biotechnology?
It is a technology based on biology, especially when used in agriculture, food
science and medicine. It refers to the use of living organisms or their products to
modify human health and environment. E.g.: in vitro fertilization, DNA vaccine
development, correcting a defective gene, synthesizing and using a gene etc.
Definition of biotechnology given by EFB (European Federation of
Biotechnology): The integration of natural science and organisms, cells, parts
thereof, and molecular analogues for products and services.
Core techniques that enabled birth of Biotechnology:
Genetic Engineering: Techniques to alter DNA/RNA to introduce into host
organisms and change their phenotype.
Maintenance of sterile conditions: Microbial contamination free ambience
to enable the growth of only the desired microbe/ eukaryotic cell for the
manufacture of antibiotics, vaccines, enzymes etc.
Three basic steps in genetically modifying an organism are:
Identification of DNA with desirable genes.
Introduction of identified DNA into the host.
Maintenance of introduced DNA in the host and transfer the DNA to its
progeny
Tools of Recombinant DNA Technology
Tools required to accomplish genetic engineering include:
1. DNA manipulative enzymes
Restriction Enzymes: Restriction enzymes serve as chemical knives to
cut genes (DNA) into defined fragments. These may then be used:
To determine the order of genes on chromosomes
, To analyze the chemical structure of genes and of regions of
DNA which regulate the functions of gene.
To create new combinations of genes.
Each restriction enzyme recognizes a specific palindrome
nucleotide sequence in DNA.
Example of a palindrome:
5’ GAATTC 3’
3’ CTTAAG 5’
Each restriction endonuclease functions by inspecting the length of a
DNA sequence. Once it finds its specific recognition sequence, it will
bind to the DNA and cut each of the two strands of the double helix at
specific points in their sugar phosphate backbones.
Polymerase enzymes: These enzymes synthesize a new strand of
DNA complementary to an existing DNA template in 5’ to 3’
direction. DNA Polymerase 1 is the one usually employed in genetic
engineering.
Ligases Enzymes: This enzyme forms phosphodiester bonds between
adjacent nucleotides and covalently links two individual fragments of
double stranded DNA by utilizing energy from cell. The enzyme used
most often in r DNA technology is T4 DNA ligase, which is enclosed by
phage T4.
2. Vectors
Vector is a carrier that delivers a foreign piece of DNA into the host
organism and they are engineered in such a way that they help in easy
linking of foreign DNA and selection of recombinants from non-
recombinants. Essential features of a vector are:
Origin of replication (ori): Sequence from where replication starts
and any piece of DNA linked to this sequence can replicate within the
host cells. A piece of DNA integrated into the genome of the recipient
can easily multiply and be inherited along with the host DNA. An
It is a technology based on biology, especially when used in agriculture, food
science and medicine. It refers to the use of living organisms or their products to
modify human health and environment. E.g.: in vitro fertilization, DNA vaccine
development, correcting a defective gene, synthesizing and using a gene etc.
Definition of biotechnology given by EFB (European Federation of
Biotechnology): The integration of natural science and organisms, cells, parts
thereof, and molecular analogues for products and services.
Core techniques that enabled birth of Biotechnology:
Genetic Engineering: Techniques to alter DNA/RNA to introduce into host
organisms and change their phenotype.
Maintenance of sterile conditions: Microbial contamination free ambience
to enable the growth of only the desired microbe/ eukaryotic cell for the
manufacture of antibiotics, vaccines, enzymes etc.
Three basic steps in genetically modifying an organism are:
Identification of DNA with desirable genes.
Introduction of identified DNA into the host.
Maintenance of introduced DNA in the host and transfer the DNA to its
progeny
Tools of Recombinant DNA Technology
Tools required to accomplish genetic engineering include:
1. DNA manipulative enzymes
Restriction Enzymes: Restriction enzymes serve as chemical knives to
cut genes (DNA) into defined fragments. These may then be used:
To determine the order of genes on chromosomes
, To analyze the chemical structure of genes and of regions of
DNA which regulate the functions of gene.
To create new combinations of genes.
Each restriction enzyme recognizes a specific palindrome
nucleotide sequence in DNA.
Example of a palindrome:
5’ GAATTC 3’
3’ CTTAAG 5’
Each restriction endonuclease functions by inspecting the length of a
DNA sequence. Once it finds its specific recognition sequence, it will
bind to the DNA and cut each of the two strands of the double helix at
specific points in their sugar phosphate backbones.
Polymerase enzymes: These enzymes synthesize a new strand of
DNA complementary to an existing DNA template in 5’ to 3’
direction. DNA Polymerase 1 is the one usually employed in genetic
engineering.
Ligases Enzymes: This enzyme forms phosphodiester bonds between
adjacent nucleotides and covalently links two individual fragments of
double stranded DNA by utilizing energy from cell. The enzyme used
most often in r DNA technology is T4 DNA ligase, which is enclosed by
phage T4.
2. Vectors
Vector is a carrier that delivers a foreign piece of DNA into the host
organism and they are engineered in such a way that they help in easy
linking of foreign DNA and selection of recombinants from non-
recombinants. Essential features of a vector are:
Origin of replication (ori): Sequence from where replication starts
and any piece of DNA linked to this sequence can replicate within the
host cells. A piece of DNA integrated into the genome of the recipient
can easily multiply and be inherited along with the host DNA. An
