TYPICAL NOTES
RECOMBINANT DNA (rDNA) TECHNOLOGY
NEET, BSc, MSc, CSIR-NET, GATE, international exams
2025
GATE
, RECOMBINANT DNA (rDNA) TECHNOLOGY
1. Introduction
Recombinant DNA Technology (also called genetic engineering or genome manipulation) refers
to the set of techniques used to isolate, cut, join, and transfer DNA from one organism to
another, creating a new combination of genetic material that does not occur naturally.
It allows scientists to:
1. Improve organisms
2. Produce therapeutic proteins
3. Correct genetic defects
4. Engineer industrial microbes
This technology forms the base of modern biotechnology.
2. Basic Concept
Recombinant DNA = "Recombined" DNA
This means DNA from two different sources is cut, joined, and inserted into a host organism.
Example:
Human insulin gene + Bacterial plasmid DNA → Recombinant DNA → Inserted into E. coli →
Human insulin production.
3. Essential Tools of rDNA Technology
A. Enzymes (Molecular Scissors & Glue)
1. Restriction Endonucleases
1. Cut DNA at specific sequences (mostly palindromic sites).
2. Types: Type I, II, III (Type II is widely used).
3. Example: EcoRI, HindIII, BamHI.
2
, EcoRI recognition site:
5' – GAATTC – 3'
3' – CTTAAG – 5'
2. DNA Ligase
o “Molecular glue” that joins DNA fragments.
3. Polymerases
o DNA polymerase for replication
o Reverse transcriptase to form cDNA from mRNA
o Taq polymerase used in PCR
B. Vectors (DNA Carriers)
Vectors carry foreign DNA into the host.
Common vectors:
1. Plasmids (pBR322, pUC19)
2. Bacteriophages (λ phage)
3. Cosmids
4. BACs (Bacterial Artificial Chromosomes)
5. YACs (Yeast Artificial Chromosomes)
6. Ti plasmid of Agrobacterium tumefaciens (plant genetic engineering)
Ideal properties of a vector:
1. Origin of replication (ori)
2. Selectable markers (Amp^R, Kan^R)
3. Cloning sites (MCS)
4. Small size
5. High copy number
C. Host Organisms
Common hosts:
1. E. coli (bacteria)
2. Yeast (Saccharomyces cerevisiae)
3. Plant cells
4. Animal cells
5. Transgenic animals
3
RECOMBINANT DNA (rDNA) TECHNOLOGY
NEET, BSc, MSc, CSIR-NET, GATE, international exams
2025
GATE
, RECOMBINANT DNA (rDNA) TECHNOLOGY
1. Introduction
Recombinant DNA Technology (also called genetic engineering or genome manipulation) refers
to the set of techniques used to isolate, cut, join, and transfer DNA from one organism to
another, creating a new combination of genetic material that does not occur naturally.
It allows scientists to:
1. Improve organisms
2. Produce therapeutic proteins
3. Correct genetic defects
4. Engineer industrial microbes
This technology forms the base of modern biotechnology.
2. Basic Concept
Recombinant DNA = "Recombined" DNA
This means DNA from two different sources is cut, joined, and inserted into a host organism.
Example:
Human insulin gene + Bacterial plasmid DNA → Recombinant DNA → Inserted into E. coli →
Human insulin production.
3. Essential Tools of rDNA Technology
A. Enzymes (Molecular Scissors & Glue)
1. Restriction Endonucleases
1. Cut DNA at specific sequences (mostly palindromic sites).
2. Types: Type I, II, III (Type II is widely used).
3. Example: EcoRI, HindIII, BamHI.
2
, EcoRI recognition site:
5' – GAATTC – 3'
3' – CTTAAG – 5'
2. DNA Ligase
o “Molecular glue” that joins DNA fragments.
3. Polymerases
o DNA polymerase for replication
o Reverse transcriptase to form cDNA from mRNA
o Taq polymerase used in PCR
B. Vectors (DNA Carriers)
Vectors carry foreign DNA into the host.
Common vectors:
1. Plasmids (pBR322, pUC19)
2. Bacteriophages (λ phage)
3. Cosmids
4. BACs (Bacterial Artificial Chromosomes)
5. YACs (Yeast Artificial Chromosomes)
6. Ti plasmid of Agrobacterium tumefaciens (plant genetic engineering)
Ideal properties of a vector:
1. Origin of replication (ori)
2. Selectable markers (Amp^R, Kan^R)
3. Cloning sites (MCS)
4. Small size
5. High copy number
C. Host Organisms
Common hosts:
1. E. coli (bacteria)
2. Yeast (Saccharomyces cerevisiae)
3. Plant cells
4. Animal cells
5. Transgenic animals
3
