Tools of Genetic Engineering :
Genetic engineering which involves isolation of a gene segment from
the whole genome, cloning of the gene into multiple copies and their
expression needs several biological tools. Some of them are given below. (Tools of Genetic Engineering)
1. Enzymes : a. Exonucleases, b. endonucleases, c. restriction endonucleases,
d. SI enzymes to convert the cohesive ends of single stranded DNA
fragments into blunt ends, e. DNA ligases, f. Alkaline phosphatase,
g.Reverse transcriptase, h. DNA polymerase etc. (Tools of Genetic Engineering)
2. Foreign DNA / Passenger DNA : It is a fragment of DNA molecule,
which is to be enzymatically isolated and cloned.
3. Cloning vectors : Vectors or vehicle DNA are those DNA that can carry
a foreign DNA fragment when inserted into it. The vectors generally used
are bacterial plasmids and bacteriophages. (Tools of Genetic Engineering)
Plasmids :
A plasmid is a circular DNA with about 200-300 nucleotides. It is
present in bacterial cells alongside their main chromosomes. A plasmid
sometimes can leave from one bacterial cell and enter another, through,
conjugation and thereby transfer genetic traits to the recepient cell.
The plasmid DNA inside a bacterium can replicate independently of the main
DNA and can depart from main genome dragging a piece of main DNA
along with it. It is called the bacterial DNA. A plasmid can sometimes fuse
with the main DNA. (Tools of Genetic Engineering)
Thus the plasmid seems to be an efficient gene exchanging
vehicle which the nature has produced.
Isolation of gene
In recombinant DNA technology, restriction endonucleases cut the
DNA double helix in very precise manner. They recognize specific base
sequences on DNA.
They cut each strand of DNA at a given place. These enzymes recognize specific DNA sequences which are called palindrome sequences. A palindrome refers to a base sequence that read the same on the two strands but in opposite directions. (Tools of Genetic Engineering)
For example if the base sequence on one strand in GAATTC read in 5’-3’ direction, the sequence on the opposite (complementary) strand is CTTAAG read in 3’-5’ direction. There is a point of symmetry within the palindrome. In the example given this point is in the center between the AT/TA. (Tools of Genetic Engineering)
5’ GAATTC 3’
3’ CTTAAG 5’
Related Topics in Zoology:
Bio Zoology All Important Topics
- MODERN GENETICS Introduction and Scope
- Human Genetics – Karyotyping
- Karyotyping of Human chromosomes
- Genetic Engineering
- Tools Of Genetic Engineering
- Restriction enzymes – Recombinant DNA Technology
- DNA – Segmenting / Fragmenting
- Genetic Diseases
- Human Genome Project (HGP)
- Cloning
- Transgenic organisms
- Gene Therapy
- Bioinformatics
- Scope of Genetic Engineering – Scope of Bioinformatics
- Database
- Genome sequencing
- Protein structure
UNIT 5. ENVIRONMENTAL SCIENCE Topic List Zoology
- Human population and explosion
- Population Explosion
- Growing Population and Environmental impacts
- Global warming – Green house effect
- Ozone layer depletion
- Prevention and Effect of Ozone depletions
- Waste management – Classification
- Management of hazardous wastes
- Management of non hazardous wastes
- Waste water treatment and management
- Biodiversity
- Conservation of Biodiversity
- Characteristics of a Bioreserve
- Energy crisis and its environmental impact
- Steps to be taken to resolve energy crisis
- Environmental impacts of Power Sources
- Poverty and environment
- Fresh water crisis and management
- Human population and explosion