genetic engenering

genetic engenering

  • Submitted By: drfaryal
  • Date Submitted: 12/07/2014 11:33 AM
  • Category: Science
  • Words: 463
  • Page: 2

Genetic Engineering
--- started in 1970s

What is genetic engineering?
The transfer of genes (segment of DNA)
from one species to another.
This is impossible in naturally breeding.

How to get the gene from species A to
species B?
A vector is used to carry the gene into the
host nucleus.

What are vectors commonly used
in GE?
Plasmid (of bacteria)
Shotgun technique (blindly shoots tiny
particles coated with the gene into the
host cells)

What is a plasmid?

Natural role of a plasmid in
Plasmids usually contain one or two
gene that confer a selective advantage
on the bacterium e.g. antibiotic
resistance gene.
Every plasmid possess a replicator gene
can duplicated independently from the
chromosomal DNA.

1&2 : antibiotic resistance genes

replicator gene

Recombinant DNA technology
Cut insulin production gene from a
human DNA
Paste it into the DNA of Escherichia coli
The E. coli reproduces rapidly to
produce large numbers: gene cloning

restriction enzyme

In bacteria, restriction enzymes
are found naturally.
They cut DNA at specific sites.

DNA double helixes are cut at the
axis of symmetry:

Cut plasmid

Cut insulin gene from
human cell

(by adding

(by adding restriction

adding ligase enzyme
Insulin gene has been inserted into the plasmid

Place the recombinant plasmids back
into the bacteria

Leave the bacteria to grow and multiply

How do I know which bacteria will have the plasmid?
Add specific antibiotics to the agar
All those bacteria which do not have the
plasmid will die
Only those with the recombinant
plasmids can grow and multiply

Application of GE:
GM Food
Industrial production
Environmental protection

Production of pharmaceuticals for
treatment of diseases e.g. human
insulin, interferons
Production of pharmaceuticals for
disease prevention e.g. vaccine
(hepatitis B...

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