2. R-DNA Technology.
Popularly known as genetic engineering, is a stream of
biotechnology which deals with manipulation of
genetic material by man in vitro.
It refers to a no. of methodologies in which
the desired genes or DNA sequences of an organism
are cut into fragments and then introduced into host
cell with or without the help of carriers or vectors to
alter its phenotype to suits human needs.
3.
4.
5. Tools of r-DNA Technology.
There are three types of bilogical tools wich are used
the synthesis of r-DNA.
1. Enzymes
2.Vehicle or vector DNA
3.Passanger DNA
6. Enzymes.
As we know that ,there are severals of specific enzyme which are used in
genetic engineering.These include:-
1. Lysing Enzymes:- These are used to open up the cell to get
DNA for genetic experiment .Lysozyme is commonly used to
dissolve the bacterial cell.
2. Cleaving Enzymes:- There are used to break DNA
molecule .They are further of three kinds:
Exonuclease
Endonuclease
Restriction endonuclease
7. 3. Synthesizing Enzymes:- These play a role in the synthesis of
DNA strands on suitable templates.They are of two types:
Reverse trancriptase
DNA Polymerase
4.Joining Enzymes:- These help in sealing gaps in DNA
fagments which are otherwise joined by complementary base
pairing .
Example.: Tu ligase act as a molecular glue.
8. Cloning vector / vehicle DNA.
The DNA used as a carrier for transferring a fragments of
foreign DNA into a suitable host is called vehicle DNA.
They are of five types:-
1. Plasmid
2. Bacteriophage DNA
3. DNA of plant and animal virus
4. Transposons
5. Artificial DNA
9. Plasmid:-
They are small extranuclear circular DNA which carry
extrachromosomal gene in bacteria and fungi.
They replicate independently.
The best known vector which are available commercially are
pBR322 & pUC18.
10. Passenger DNA
It is the DNA which is transferred from one organism into another by
combining it with the vehicle DNA.
Three types of DNA are used as-
1. C-DNA:- it is synthesized on RNA template with the help of
reverse transcriptase enzymw and necessarry nucleotide.
2. S-DNA:- it is synthesize with the help of DNA polymerase on
DNA template or form free deoxy ribonucleotides without a
template.
3. Random DNA:- it refers to small fragments formed bg breaking a
chromosome of an organism with the help of restriction
endonuclease.